The Association Between Television Viewing and Irregular Sleep Schedules Among Children Less Than 3 Years of Age
http://www.100md.com
《小儿科》
Robert Wood Johnson Clinical Scholars Program
Department of Pediatrics
Child Health Institute, University of Washington, Seattle, Washington
Children’s Hospital and Regional Medical Center, Seattle, Washington
ABSTRACT
Background. Regular sleep schedules are an important part of healthy sleep habits. Although television viewing is associated with altered sleep patterns and sleep disorders among children and adolescents, the effect of television viewing on the sleep patterns of infants and toddlers is not known.
Objective. To test the hypothesis that television viewing by infants and toddlers is associated with having irregular naptime and bedtime schedules.
Methods. We used data from the National Survey of Early Childhood Health, a nationally representative, cross-sectional study of the health and health care of children 4 to 35 months of age. Our main outcome measures were whether children had irregular naptime and bedtime schedules. Our main predictor was hours of television watched on a daily basis. We performed multivariate logistic regression analyses, adjusting for a variety of factors including demographic information, measures of maternal mental health, and measures of family interactions, to test the independent association of television viewing and irregular naptime and bedtime schedules.
Results. Data were available for 2068 children. Thirty-four percent of all children had irregular naptime schedules, and 27% had irregular bedtime schedules. Mean hours of television viewing per day were as follows: 0.9 hours/day (95% confidence interval [CI]: 0.8–1.0 hours/day) for children <12 months of age, 1.6 hours/day (95% CI: 1.4–1.8 hours/day) for children 12 to 23 months of age, and 2.3 hours/day (95% CI: 2.1–2.5 hours/day) for children 24 to 35 months of age. In our logistic regression model, the number of hours of television watched per day was associated with both an irregular naptime schedule (odds ratio: 1.09; 95% CI: 1.01–1.18) and an irregular bedtime schedule (odds ratio: 1.13; 95% CI: 1.04–1.24).
Conclusions. Television viewing among infants and toddlers is associated with irregular sleep schedules. More research is warranted to determine whether this association is causal.
Key Words: television sleep prevention infants toddlers
Abbreviations: CI, confidence interval MHI-5, 5-item Mental Health Inventory
Children in the United States watch >19 hours of television per week.1 Notably, this viewing begins very early in life and may be increasing, given recent attempts to market television to younger viewers.2,3 Recent studies have shown that significant proportions of infants and toddlers exceed the American Academy of Pediatrics recommendations that children <2 years of age should not watch any television and those >2 years of age should be limited to <2 hours per day.2,4,5
Many adverse effects of television viewing on children and adolescents have been documented. These effects include obesity,6–9 aggressive behavior,10–12 decreased physical activity,13 attention problems,14 and sleep disorders.15–18 Considerably less research, however, has focused on the impact of television viewing on infants and toddlers, despite the fact that they spend large and potentially increasing proportions of time with media.2
Healthy sleep habits are an important part of ensuring high-quality sleep.19,20 Television viewing, among school-aged children and adolescents, has been shown to be associated with poor sleep habits and disordered sleep.15–18,21 Cross-sectional studies found that television/videotape viewing was associated with late bedtimes and sleep disturbances among school-aged children and adolescents.15,17 One longitudinal study demonstrated that high levels of television viewing during adolescence might lead to the development of sleep problems in early adulthood.16 Whether television viewing has an impact on the sleep patterns of infants and toddlers is unknown, although good sleep hygiene is no less important for this group of children.
Several theories have been proposed as potential mechanisms to explain the association between television viewing and sleep disturbances.15,16 One theory is that television may have an actual physiologic impact on its viewers. It may be that the bright light of the television before sleep affects the sleep/wake cycle through suppression of the release of melatonin.22,23 A second theory is that television may have a psychologic impact on its viewers. Children may watch programs that are developmentally inappropriate for their ages or have violent content. Violent programming has been shown to have a negative impact on children’s behavior10,12,24–26 and may also inhibit the relaxation necessary for sleep induction, although this has not been demonstrated.15 A third potential mechanism explaining the relationship between television viewing and sleep disturbances is parental priorities. Parents of children who watch significant amounts of television may be poor limit-setters in general and not enforce rules with regard to both television viewing and regular sleep times.
Sleep problems are very common among children, ranging in prevalence from 25% to 69%.27,28 Because of this fact, as well as the lack of information on the impact of television viewing on the sleep of infants and toddlers, we conducted a retrospective cohort study to test the hypothesis that television viewing by infants and toddlers would be associated with irregular naptime and bedtime schedules.
METHODS
Data Source
The National Survey of Early Childhood Health was a collaborative effort by the Gerber Foundation, the American Academy of Pediatrics, the Center for Healthier Children, Families, and Communities at the University of California, Los Angeles, and the National Center for Health Statistics. The goal of the survey was to acquire a better understanding of parental perceptions of pediatric health and health care. During the first half of 2000, a nationally representative sample of 2068 households with children 4 to 35 months of age was surveyed with a stratified, random-digit-dial telephone system. Black and/or Hispanic children were oversampled. Data were collected from the parent or guardian self-identified as being most responsible for the health care needs of the child. Of respondents, 87% were the mothers of the children of interest.29 A computer-assisted, telephone interview instrument was used. Interviews were 30 minutes in duration. If >1 child resided in the household, then 1 child was selected randomly to be the target of the interview. Interviews were performed in English and Spanish. Survey questions were designed to acquire information regarding the child’s health care and factors associated with this care, as well as information on parenting activities and the home environment. More information regarding this dataset is available in other sources.29,30
Measures
The outcome variables of bedtime and naptime sleep schedules were evaluated from data collected from responses to the following questions. (1) Is the child’s bedtime usually the same from day to day or does is it change from day to day (2) Is the child’s naptime usually the same from day to day or does is it change from day to day Naptime and bedtime schedules that changed from day to day were noted as varied/irregular.
Our main predictor variable of television viewing was evaluated with data from the following question: In a typical day, about how many hours does your child spend watching TV or videos Answers ranged from 0 to 24 hours, and partial hours were rounded up.
Other independent variables were selected from the following survey domains: demographic and household information, maternal health, and family interactions. Demographic and household information included household income, the child’s age and gender, the interview language, the number of children in the household, and maternal education level, employment status, age, marital status, and race/ethnicity. Maternal education data were collapsed into 2 options: less than high school or high school degree and above. Employment status was defined as full-time, part-time, or not employed. Marital status was collapsed into married or not married. Not married included respondents who stated they were divorced, widowed, separated, or never married. The mother’s race/ethnicity was classified as non-Hispanic white, non-Hispanic black, Hispanic, or other non-Hispanic. The mother’s race/ethnicity was used instead of the child’s race/ethnicity because culture may influence sleep habits31 and we thought that the mother’s race/ethnicity would be more representative of the cultural environment of a child <3 years of age than the child’s own race/ethnicity. The variable for the mother’s race/ethnicity was created by taking data from questions regarding maternal race and reported maternal Hispanic ethnicity. Maternal race was collapsed into white, black, or other. All those with a positive response to the question regarding maternal Hispanic ethnicity were then recoded as Hispanic for this variable, to create the options non-Hispanic white, non-Hispanic black, Hispanic, and other non-Hispanic.
Maternal support variables included data from the following yes/no questions. (1) Is there someone you can turn to for day-to-day emotional help with parenting (2) Is there someone you can count on to watch your child if you need a break Maternal mental health data were determined from the 5-item Mental Health Inventory (MHI-5) and the following question: in general, how well do you feel you are coping with the day-to-day demands of parenthood (very well, somewhat well, not very well, or not well at all) Data from responses to this question were collapsed into very well or less than very well. The MHI-5 is a measure of emotional status32 and consists of the following questions: how much of the time during the past month have you (1) been a very nervous person, (2) felt calm and peaceful (reverse scored), (3) felt downhearted and blue, (4) felt so down in the dumps that nothing can cheer you up, and (5) been a happy person (reverse scored) A 6-point Likert scale ranging from all of the time to none of the time was used for each question. Responses to the 5 questions were summed; scores could range from 5 to 30, with higher scores reflecting better emotional well-being.
Measures of family interactions included the total number of children’s books at home, the frequency of reading to the child in a typical week, which was collapsed into reading to the child 3 times per week or less, and hours spent in child care. In addition, data from the following questions were included. (1) In a typical day, how often would you say you feel frustrated or aggravated with your child’s behavior This was collapsed into 2 options: rarely/never or sometimes/always. (2) Would you say that you spend the right amount of time with your child or would you like to spend a lot more time, a little more time, a little less time, or a lot less time This was recoded into 3 options: right amount, more time, or less time.
Finally, to adjust for the possibility that a general parental inability to structure and to schedule activities might confound our findings, we included having a regular mealtime as a covariate. These data were gathered in response to the following question: Are your child’s mealtimes usually the same every day or do they change from day to day For all variables used in this study, responses of "don’t know" and refusals were recoded as missing for the analysis.
Analyses
Multivariate logistic regression analysis was performed to determine the independent association between having irregular naptime and bedtime schedules and television viewing, with adjustment for all of the covariates detailed above. Sampling weights were used to adjust for the survey’s complex sampling frame and to provide estimates for the US population. Having a regular mealtime was also tested, to determine whether it was an effect modifier, by using an interaction term of mealtime-television hours. The P value associated with this interaction term was not significant in either the naptime or bedtime models. All statistical analyses were performed with Intercooled Stata 8.2 for Windows (Stata Corp, College Station, TX).
RESULTS
In Table 1 we present characteristics of the sample population, with US population estimates in the categories of demographic and household information, family interactions, and maternal health. Of the 2068 respondents, 440 identified themselves as non-Hispanic black and 728 as Hispanic. Sixty-nine percent of mothers were married, 21% had not finished high school, and 35% had annual household incomes below $25000. The child’s ages were as follows: 26% were between 4 and 11 months of age, 39% were between 12 and 23 months, and 36% were between 24 and 35 months.
Overall, 86% of respondents thought that they had emotional support for their parenting, 88% had someone who could give them a break from parenting if needed, 63% thought that they were coping very well with the demands of parenthood, and 60% were rarely or never frustrated with their children. Approximately 25% of respondents had varied daily mealtimes.
Almost 34% of children had varied naptime schedules, and 27% had varied bedtime schedules. Mean hours per day of television viewing were as follows: 0.9 hours/day (95% confidence interval [CI]: 0.8–1.0 hours/day) for children <12 months of age, 1.6 hours/day (95% CI: 1.4–1.8 hours/day) for children 12 to 23 months of age, and 2.3 hours/day (95% CI: 2.1–2.5 hours/day) for children 24 to 35 months of age.
In our logistic regression model, the number of hours of television watched per day was associated with both varied naptimes (odds ratio: 1.09; 95% CI: 1.01–1.18) and varied bedtimes (odds ratio: 1.13; 95% CI: 1.04–1.24) (Table 2). Notably, having a varied mealtime schedule was associated with both irregular naptimes (odds ratio: 2.50; 95% CI: 1.74–3.59) and irregular bedtimes (odds ratio: 2.29; 95% CI: 1.63–3.21).
DISCUSSION
We found that television viewing among infants and toddlers was associated with an increased risk of having an irregular sleep schedule. This was independent of many other factors that could affect a child’s sleep schedule, such as household and demographic factors, maternal health, and family interactions, as well as parental ability to maintain regular mealtimes.
These findings are potentially important, because a routinized sleep schedule is a critical component of ensuring good sleep.19,20,33–35 Irregular sleep schedules can lead to inadequate sleep time and sleep problems. Studies among adults have revealed that alterations in sleep schedules can affect the sleep/wake cycle and lead to inadequate sleep.36–38 Irregular sleep schedules can also be a sign of a sleep problem. Furthermore, inadequate sleep among adults has been linked to impaired immune function, inability to concentrate, memory deficits, and emotional instability.37,39–42 Inadequate sleep and sleep problems among children can have effects on both the child and the parent. Consequences for the child may include problems of mood, behavior, and learning, and poor health outcomes.20 It is also easy to imagine that a child’s sleep problem could lead to inadequate sleep for the parent, thus putting the parent at risk for, at a minimum, mood imbalances and poor parenting.20 Adequate, high-quality sleep, promoted by routine sleep schedules, is important to the overall well-being of children and parents.
Our findings are consistent with studies conducted among older children and adults that found associations between television viewing and disordered sleep. An ongoing controversy remains regarding whether the causal relationship is actually reversed, ie, insomnia leads to increased viewing. This could certainly be true for older children and adults but seems less plausible in the case of infants and toddlers, who exert no independent control over the television. It is possible, but disconcerting, that parents would use television for children in this age group who were having difficulty sleeping. This might explain why 30% of young children have televisions in their bedrooms.2 However, television viewing may simply be part of their usual sleep routine. Owens et al15 found that, for young school children, 75% of parents reported television viewing as a usual part of their child’s routine and 90% did not think that it had a significant impact on the sleep of their child. Additional research to clarify this relationship is warranted.
There are several limitations to this study that deserve comment. First, our data are cross-sectional, which precludes us from making causal inferences. However, as discussed above, it is plausible that television viewing leads to disordered sleep in this young population. Second, although we tried to control for many potential confounding factors that could affect the daily schedule or simply the sleep schedule of an infant or toddler, our adjustment might well have been imperfect. Parents who are unable to exert control over television viewing may also be unable to ensure a daily routine and regular sleep times. We attempted to control for this by including having a regular mealtime in our regression analyses, as a proxy for having a general daily routine; in fact, irregular mealtimes were associated with irregular naptime and bedtime schedules, which suggests that we were somewhat able to control for a general inability to maintain schedules. Third, the data on television viewing for this population came from parental reports. Although this method has been shown to be correlated with actual hours viewed,43 its subjective nature raises the possibility of measurement error. However, random measurement error reduces the ability to detect an effect in data by biasing results toward the null.44 Therefore, our significant findings despite the existence of measurement error suggest that, if anything, the true effect may be stronger than we were able to identify. Finally, our data were limited to the regularity of sleep schedules, rather than the quantity and quality of actual sleep. Therefore, we were unable to explore more fully the relationship of television viewing and sleep in this population.
Although they were not part of our study hypothesis, other factors were found to be associated with irregular sleep schedules in our population and are interesting to note. For both bedtime and naptime schedules, varied mealtimes were associated with a greater chance of having an irregular schedule. Maternal factors were also associated with irregular sleep schedules. Lacking emotional support for parenting and being unmarried were associated with varied naptimes. A high school education or more was associated with consistent bedtimes.
In 2001, the American Academy of Pediatrics created guidelines for television viewing. Children <2 years of age should not watch television and children >2 years of age should limit their time with entertainment media to 2 hours per day.6 The impact of television viewing on sleep schedules for infants and toddlers was not included as a reason for these guidelines. This study may add one more reason why pediatricians, parents, and society should support these guidelines for limited television viewing times.
ACKNOWLEDGMENTS
Support for this study was provided by the Robert Wood Johnson Foundation through the Robert Wood Johnson Clinical Scholars Program.
FOOTNOTES
Accepted Jan 7, 2005.
The opinions in this article are those of the authors and not the Robert Wood Johnson Foundation.
No conflict of interest declared.
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Johnson JG, Cohen P, Kasen S, First MB, Brook JS. Association between television viewing and sleep problems during adolescence and early adulthood. Arch Pediatr Adolesc Med. 2004;158 :562 –568
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Department of Pediatrics
Child Health Institute, University of Washington, Seattle, Washington
Children’s Hospital and Regional Medical Center, Seattle, Washington
ABSTRACT
Background. Regular sleep schedules are an important part of healthy sleep habits. Although television viewing is associated with altered sleep patterns and sleep disorders among children and adolescents, the effect of television viewing on the sleep patterns of infants and toddlers is not known.
Objective. To test the hypothesis that television viewing by infants and toddlers is associated with having irregular naptime and bedtime schedules.
Methods. We used data from the National Survey of Early Childhood Health, a nationally representative, cross-sectional study of the health and health care of children 4 to 35 months of age. Our main outcome measures were whether children had irregular naptime and bedtime schedules. Our main predictor was hours of television watched on a daily basis. We performed multivariate logistic regression analyses, adjusting for a variety of factors including demographic information, measures of maternal mental health, and measures of family interactions, to test the independent association of television viewing and irregular naptime and bedtime schedules.
Results. Data were available for 2068 children. Thirty-four percent of all children had irregular naptime schedules, and 27% had irregular bedtime schedules. Mean hours of television viewing per day were as follows: 0.9 hours/day (95% confidence interval [CI]: 0.8–1.0 hours/day) for children <12 months of age, 1.6 hours/day (95% CI: 1.4–1.8 hours/day) for children 12 to 23 months of age, and 2.3 hours/day (95% CI: 2.1–2.5 hours/day) for children 24 to 35 months of age. In our logistic regression model, the number of hours of television watched per day was associated with both an irregular naptime schedule (odds ratio: 1.09; 95% CI: 1.01–1.18) and an irregular bedtime schedule (odds ratio: 1.13; 95% CI: 1.04–1.24).
Conclusions. Television viewing among infants and toddlers is associated with irregular sleep schedules. More research is warranted to determine whether this association is causal.
Key Words: television sleep prevention infants toddlers
Abbreviations: CI, confidence interval MHI-5, 5-item Mental Health Inventory
Children in the United States watch >19 hours of television per week.1 Notably, this viewing begins very early in life and may be increasing, given recent attempts to market television to younger viewers.2,3 Recent studies have shown that significant proportions of infants and toddlers exceed the American Academy of Pediatrics recommendations that children <2 years of age should not watch any television and those >2 years of age should be limited to <2 hours per day.2,4,5
Many adverse effects of television viewing on children and adolescents have been documented. These effects include obesity,6–9 aggressive behavior,10–12 decreased physical activity,13 attention problems,14 and sleep disorders.15–18 Considerably less research, however, has focused on the impact of television viewing on infants and toddlers, despite the fact that they spend large and potentially increasing proportions of time with media.2
Healthy sleep habits are an important part of ensuring high-quality sleep.19,20 Television viewing, among school-aged children and adolescents, has been shown to be associated with poor sleep habits and disordered sleep.15–18,21 Cross-sectional studies found that television/videotape viewing was associated with late bedtimes and sleep disturbances among school-aged children and adolescents.15,17 One longitudinal study demonstrated that high levels of television viewing during adolescence might lead to the development of sleep problems in early adulthood.16 Whether television viewing has an impact on the sleep patterns of infants and toddlers is unknown, although good sleep hygiene is no less important for this group of children.
Several theories have been proposed as potential mechanisms to explain the association between television viewing and sleep disturbances.15,16 One theory is that television may have an actual physiologic impact on its viewers. It may be that the bright light of the television before sleep affects the sleep/wake cycle through suppression of the release of melatonin.22,23 A second theory is that television may have a psychologic impact on its viewers. Children may watch programs that are developmentally inappropriate for their ages or have violent content. Violent programming has been shown to have a negative impact on children’s behavior10,12,24–26 and may also inhibit the relaxation necessary for sleep induction, although this has not been demonstrated.15 A third potential mechanism explaining the relationship between television viewing and sleep disturbances is parental priorities. Parents of children who watch significant amounts of television may be poor limit-setters in general and not enforce rules with regard to both television viewing and regular sleep times.
Sleep problems are very common among children, ranging in prevalence from 25% to 69%.27,28 Because of this fact, as well as the lack of information on the impact of television viewing on the sleep of infants and toddlers, we conducted a retrospective cohort study to test the hypothesis that television viewing by infants and toddlers would be associated with irregular naptime and bedtime schedules.
METHODS
Data Source
The National Survey of Early Childhood Health was a collaborative effort by the Gerber Foundation, the American Academy of Pediatrics, the Center for Healthier Children, Families, and Communities at the University of California, Los Angeles, and the National Center for Health Statistics. The goal of the survey was to acquire a better understanding of parental perceptions of pediatric health and health care. During the first half of 2000, a nationally representative sample of 2068 households with children 4 to 35 months of age was surveyed with a stratified, random-digit-dial telephone system. Black and/or Hispanic children were oversampled. Data were collected from the parent or guardian self-identified as being most responsible for the health care needs of the child. Of respondents, 87% were the mothers of the children of interest.29 A computer-assisted, telephone interview instrument was used. Interviews were 30 minutes in duration. If >1 child resided in the household, then 1 child was selected randomly to be the target of the interview. Interviews were performed in English and Spanish. Survey questions were designed to acquire information regarding the child’s health care and factors associated with this care, as well as information on parenting activities and the home environment. More information regarding this dataset is available in other sources.29,30
Measures
The outcome variables of bedtime and naptime sleep schedules were evaluated from data collected from responses to the following questions. (1) Is the child’s bedtime usually the same from day to day or does is it change from day to day (2) Is the child’s naptime usually the same from day to day or does is it change from day to day Naptime and bedtime schedules that changed from day to day were noted as varied/irregular.
Our main predictor variable of television viewing was evaluated with data from the following question: In a typical day, about how many hours does your child spend watching TV or videos Answers ranged from 0 to 24 hours, and partial hours were rounded up.
Other independent variables were selected from the following survey domains: demographic and household information, maternal health, and family interactions. Demographic and household information included household income, the child’s age and gender, the interview language, the number of children in the household, and maternal education level, employment status, age, marital status, and race/ethnicity. Maternal education data were collapsed into 2 options: less than high school or high school degree and above. Employment status was defined as full-time, part-time, or not employed. Marital status was collapsed into married or not married. Not married included respondents who stated they were divorced, widowed, separated, or never married. The mother’s race/ethnicity was classified as non-Hispanic white, non-Hispanic black, Hispanic, or other non-Hispanic. The mother’s race/ethnicity was used instead of the child’s race/ethnicity because culture may influence sleep habits31 and we thought that the mother’s race/ethnicity would be more representative of the cultural environment of a child <3 years of age than the child’s own race/ethnicity. The variable for the mother’s race/ethnicity was created by taking data from questions regarding maternal race and reported maternal Hispanic ethnicity. Maternal race was collapsed into white, black, or other. All those with a positive response to the question regarding maternal Hispanic ethnicity were then recoded as Hispanic for this variable, to create the options non-Hispanic white, non-Hispanic black, Hispanic, and other non-Hispanic.
Maternal support variables included data from the following yes/no questions. (1) Is there someone you can turn to for day-to-day emotional help with parenting (2) Is there someone you can count on to watch your child if you need a break Maternal mental health data were determined from the 5-item Mental Health Inventory (MHI-5) and the following question: in general, how well do you feel you are coping with the day-to-day demands of parenthood (very well, somewhat well, not very well, or not well at all) Data from responses to this question were collapsed into very well or less than very well. The MHI-5 is a measure of emotional status32 and consists of the following questions: how much of the time during the past month have you (1) been a very nervous person, (2) felt calm and peaceful (reverse scored), (3) felt downhearted and blue, (4) felt so down in the dumps that nothing can cheer you up, and (5) been a happy person (reverse scored) A 6-point Likert scale ranging from all of the time to none of the time was used for each question. Responses to the 5 questions were summed; scores could range from 5 to 30, with higher scores reflecting better emotional well-being.
Measures of family interactions included the total number of children’s books at home, the frequency of reading to the child in a typical week, which was collapsed into reading to the child 3 times per week or less, and hours spent in child care. In addition, data from the following questions were included. (1) In a typical day, how often would you say you feel frustrated or aggravated with your child’s behavior This was collapsed into 2 options: rarely/never or sometimes/always. (2) Would you say that you spend the right amount of time with your child or would you like to spend a lot more time, a little more time, a little less time, or a lot less time This was recoded into 3 options: right amount, more time, or less time.
Finally, to adjust for the possibility that a general parental inability to structure and to schedule activities might confound our findings, we included having a regular mealtime as a covariate. These data were gathered in response to the following question: Are your child’s mealtimes usually the same every day or do they change from day to day For all variables used in this study, responses of "don’t know" and refusals were recoded as missing for the analysis.
Analyses
Multivariate logistic regression analysis was performed to determine the independent association between having irregular naptime and bedtime schedules and television viewing, with adjustment for all of the covariates detailed above. Sampling weights were used to adjust for the survey’s complex sampling frame and to provide estimates for the US population. Having a regular mealtime was also tested, to determine whether it was an effect modifier, by using an interaction term of mealtime-television hours. The P value associated with this interaction term was not significant in either the naptime or bedtime models. All statistical analyses were performed with Intercooled Stata 8.2 for Windows (Stata Corp, College Station, TX).
RESULTS
In Table 1 we present characteristics of the sample population, with US population estimates in the categories of demographic and household information, family interactions, and maternal health. Of the 2068 respondents, 440 identified themselves as non-Hispanic black and 728 as Hispanic. Sixty-nine percent of mothers were married, 21% had not finished high school, and 35% had annual household incomes below $25000. The child’s ages were as follows: 26% were between 4 and 11 months of age, 39% were between 12 and 23 months, and 36% were between 24 and 35 months.
Overall, 86% of respondents thought that they had emotional support for their parenting, 88% had someone who could give them a break from parenting if needed, 63% thought that they were coping very well with the demands of parenthood, and 60% were rarely or never frustrated with their children. Approximately 25% of respondents had varied daily mealtimes.
Almost 34% of children had varied naptime schedules, and 27% had varied bedtime schedules. Mean hours per day of television viewing were as follows: 0.9 hours/day (95% confidence interval [CI]: 0.8–1.0 hours/day) for children <12 months of age, 1.6 hours/day (95% CI: 1.4–1.8 hours/day) for children 12 to 23 months of age, and 2.3 hours/day (95% CI: 2.1–2.5 hours/day) for children 24 to 35 months of age.
In our logistic regression model, the number of hours of television watched per day was associated with both varied naptimes (odds ratio: 1.09; 95% CI: 1.01–1.18) and varied bedtimes (odds ratio: 1.13; 95% CI: 1.04–1.24) (Table 2). Notably, having a varied mealtime schedule was associated with both irregular naptimes (odds ratio: 2.50; 95% CI: 1.74–3.59) and irregular bedtimes (odds ratio: 2.29; 95% CI: 1.63–3.21).
DISCUSSION
We found that television viewing among infants and toddlers was associated with an increased risk of having an irregular sleep schedule. This was independent of many other factors that could affect a child’s sleep schedule, such as household and demographic factors, maternal health, and family interactions, as well as parental ability to maintain regular mealtimes.
These findings are potentially important, because a routinized sleep schedule is a critical component of ensuring good sleep.19,20,33–35 Irregular sleep schedules can lead to inadequate sleep time and sleep problems. Studies among adults have revealed that alterations in sleep schedules can affect the sleep/wake cycle and lead to inadequate sleep.36–38 Irregular sleep schedules can also be a sign of a sleep problem. Furthermore, inadequate sleep among adults has been linked to impaired immune function, inability to concentrate, memory deficits, and emotional instability.37,39–42 Inadequate sleep and sleep problems among children can have effects on both the child and the parent. Consequences for the child may include problems of mood, behavior, and learning, and poor health outcomes.20 It is also easy to imagine that a child’s sleep problem could lead to inadequate sleep for the parent, thus putting the parent at risk for, at a minimum, mood imbalances and poor parenting.20 Adequate, high-quality sleep, promoted by routine sleep schedules, is important to the overall well-being of children and parents.
Our findings are consistent with studies conducted among older children and adults that found associations between television viewing and disordered sleep. An ongoing controversy remains regarding whether the causal relationship is actually reversed, ie, insomnia leads to increased viewing. This could certainly be true for older children and adults but seems less plausible in the case of infants and toddlers, who exert no independent control over the television. It is possible, but disconcerting, that parents would use television for children in this age group who were having difficulty sleeping. This might explain why 30% of young children have televisions in their bedrooms.2 However, television viewing may simply be part of their usual sleep routine. Owens et al15 found that, for young school children, 75% of parents reported television viewing as a usual part of their child’s routine and 90% did not think that it had a significant impact on the sleep of their child. Additional research to clarify this relationship is warranted.
There are several limitations to this study that deserve comment. First, our data are cross-sectional, which precludes us from making causal inferences. However, as discussed above, it is plausible that television viewing leads to disordered sleep in this young population. Second, although we tried to control for many potential confounding factors that could affect the daily schedule or simply the sleep schedule of an infant or toddler, our adjustment might well have been imperfect. Parents who are unable to exert control over television viewing may also be unable to ensure a daily routine and regular sleep times. We attempted to control for this by including having a regular mealtime in our regression analyses, as a proxy for having a general daily routine; in fact, irregular mealtimes were associated with irregular naptime and bedtime schedules, which suggests that we were somewhat able to control for a general inability to maintain schedules. Third, the data on television viewing for this population came from parental reports. Although this method has been shown to be correlated with actual hours viewed,43 its subjective nature raises the possibility of measurement error. However, random measurement error reduces the ability to detect an effect in data by biasing results toward the null.44 Therefore, our significant findings despite the existence of measurement error suggest that, if anything, the true effect may be stronger than we were able to identify. Finally, our data were limited to the regularity of sleep schedules, rather than the quantity and quality of actual sleep. Therefore, we were unable to explore more fully the relationship of television viewing and sleep in this population.
Although they were not part of our study hypothesis, other factors were found to be associated with irregular sleep schedules in our population and are interesting to note. For both bedtime and naptime schedules, varied mealtimes were associated with a greater chance of having an irregular schedule. Maternal factors were also associated with irregular sleep schedules. Lacking emotional support for parenting and being unmarried were associated with varied naptimes. A high school education or more was associated with consistent bedtimes.
In 2001, the American Academy of Pediatrics created guidelines for television viewing. Children <2 years of age should not watch television and children >2 years of age should limit their time with entertainment media to 2 hours per day.6 The impact of television viewing on sleep schedules for infants and toddlers was not included as a reason for these guidelines. This study may add one more reason why pediatricians, parents, and society should support these guidelines for limited television viewing times.
ACKNOWLEDGMENTS
Support for this study was provided by the Robert Wood Johnson Foundation through the Robert Wood Johnson Clinical Scholars Program.
FOOTNOTES
Accepted Jan 7, 2005.
The opinions in this article are those of the authors and not the Robert Wood Johnson Foundation.
No conflict of interest declared.
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