Gap between the concerns of healthcare professionals and parents' perceptions regarding dietary habits for 18-month- and 3-year-old children in Japan.

BACKGROUND: A gap has been reported between healthcare professionals' (hereafter "professionals") recognition of preschool children's diets and parents' perception of concern. This study investigated the gap between the concerns reported by professionals and parents' perceptions regarding health and dietary habits by age (18 months and 3 years) and gender in Japan. METHODS: The study design consisted of a cross-sectional, multilevel survey. The request letters were sent to all households with target children with the cooperation of local governments. After obtaining written informed consent from parents, questionnaires were distributed to them. The survey included 30 items on children's concerns about health and dietary habits. At the health checkup, parents indicated whether they were concerned in response to each item, and responded child's height and weight and birth height and weight. Next, the professionals provided counseling to the parents at a health checkup. After that, the professionals noted their concerns in response to the same 30 items as those given to parents. The participation rates were 82.9% (18 months) and 82.8% (3 years). Data of 239 persons for 18 months and 223 persons for 3 years old were analyzed. In the statistical analysis, the items that were judged as concerning by professionals but not by parents were identified; likewise, the items that were of concern to parents but not to professionals were identified. Sensitivity, false negative rate, specificity, false positive rate, and Youden index were calculated to analyze the discordance rate for each item. RESULTS: Many parents in this study were concerned about the issues that professionals did not consider to be concerning. Moreover, the parents worried about more issues for 3-year-olds than for 18-month-olds. The items for which ≥ 10 professionals indicated concerns and with higher discordance between the professionals and parents for both boys and girls were "picky eating" for 18-month-olds and "inconsistent amount of food" for 3-year-olds. CONCLUSIONS: The concerns that professionals have with respect to children's diets and the things that parents worry about show gaps. It might be necessary to provide professional counseling for parents to develop a correct understanding of their children's dietary habits.

Relationship between parents' dietary care and food diversity among preschool children in Japan.

OBJECTIVE: To identify the relationship between preschool children's dietary diversity and parents' care behaviours related to their diet including contents of foods and snacks, mealtime practice and parent-child communication. DESIGN: Cross-sectional study. Data were extracted from the National Nutrition Survey on Preschool Children in 2015 by Japan's Ministry of Health, Labour and Welfare. SETTING: The distribution of food diversity score (FDS) (maximum of eight points) was confirmed. The participants were divided into higher (≥4 points) and lower (≤3 points) food diversity groups. A comparison between the two groups examined parents' socio-economic status, children's health and living conditions, and parental care concerning children's diets (thirteen items). A multiple regression analysis was performed relating FDS to the factors of parental socio-economic status and child health, and a logistic regression analysis was conducted to identify factors of parental care related to the higher food diversity group. PARTICIPANTS: 2143 persons from households with children aged 2-6 years. RESULTS: Parental care concerning children's diets was the factor most strongly associated with children's FDS. Those factors most strongly associated with higher food diversity were nutritional balance of foods (OR: 1·76; 95 % CI 1·44, 2·16; P < 0 0001), snack contents (OR: 1·41; 95 % CI 1·07, 1·86; P = 0·014) and regular mealtimes (OR: 1·30; 95 % CI 1·08, 1·55; P = 0·005). CONCLUSIONS: The findings indicate the importance of parents paying attention to the contents of children's foods and snacks, ensuring that children eat regularly, and increasing the diversity of their diets.

Factors associated with birthweight decline in Japan (1980-2004).

BACKGROUND: Birthweight has been declining consistently for more than 30 years in Japan. This rapid rise in low birthweight is one of the worst among the countries of the Organization for Economic Co-operation and Development. We examined potential determinants of birthweight decline in Japan. METHODS: We used population-based birth certificate data from vital statistics records and retrieved 40,968,266 birth certificates of neonates born between 1980 and 2004. We analyzed time trends using linear regression analysis in examining whether the decline in birthweight could be explained by obstetrical variables such as gestational age and multiple gestations. RESULTS: From 1980 to 2004, we observed a decline in mean birthweight with a yearly effect of - 8.07 g, which became steeper after 1985, persisted until 1999, and plateaued thereafter. After adjusting for gestational age, gender, birth order, multiple gestations, and fathers' age, the yearly effect between 1980 and 2004 persisted at - 5.13 g. CONCLUSION: Recent decreases in birthweight among Japanese neonates were not fully explained by trends in gestational age, gender, birth order, multiple gestations, and fathers' age. Thus, additional factors such as pre-pregnancy maternal body mass index (BMI) and maternal diet should be considered. Reducing the rate of induced deliveries and improving the BMI or diet of young women should be a public health priority.

Policy statement of enteral nutrition for preterm and very low birthweight infants.

For preterm and very low birthweight infants, the mother's own milk is the best nutrition. Based on the latest information for mothers who give birth to preterm and very low birthweight infants, medical staff should encourage and assist mothers to pump or express and provide their own milk whenever possible. If the supply of maternal milk is insufficient even though they receive adequate support, or the mother's own milk cannot be given to her infant for any reason, donor human milk should be used. Donors who donate their breast milk need to meet the Guideline of the Japan Human Milk Bank Association. Donor human milk should be provided according to the medical needs of preterm and very low birthweight infants, regardless of their family's financial status. In the future, it will be necessary to create a system to supply an exclusive human milk-based diet (EHMD), consisting of human milk with the addition of a human milk-derived human milk fortifier, to preterm and very low birthweight infants.

Development and validation of a food frequency questionnaire (FFQ) for assessing dietary macronutrients and calcium intake in Cambodian school-aged children.

BACKGROUND: The nutritional status of school-aged children in Cambodia remains largely unknown. No tools for large-scale assessment of daily nutrient intake exist for this population, making development of appropriate intervention strategies difficult. Thus, we aimed to devise and validate a food frequency questionnaire (FFQ) that is suitable for and dedicated to assessing the dietary intake of macronutrients and calcium in school-aged children in Cambodia. METHODS: We developed an FFQ based on data from a single 24-h recall survey of 2020 children. The final list, which was developed as specified in the Block method and stepwise multiple regression analysis, comprised of 56 food items covering intake of energy, macronutrients, and calcium. We assessed the validity of the FFQ by comparison with a duplicated 24-h recall survey before and after de-attenuation. We also tested the reproducibility by comparing the first and second FFQs (FFQ1 and FFQ2) administered at an interval of approximately 6 weeks. RESULTS: The 56 food items in the FFQ accounted for 73.3% of the dietary calcium intake of Cambodian children and explained most of the inter-individual variation (cumulative R2: 0.96). The intake estimated by the FFQ was lower than the average intake across the two 24-h recall surveys. Spearman's correlation coefficients for comparison between FFQ1 and FFQ2 ranged from 0.29 for fat to 0.47 for calcium. After de-attenuation of data, Pearson's correlation coefficients ranged from 0.38 for fat to 0.71 for energy. Cross-classification analysis indicated that the average percentage of the subjects classified in the same or adjacent quartiles was 78.0%. CONCLUSIONS: The FFQ is potentially a reliable scale for measuring nutrient intake in this population.

Parent-child cooking meal together may relate to parental concerns about the diets of their toddlers and preschoolers: a cross-sectional analysis in Japan.

BACKGROUND: Parents often have concerns about the food habits of their young children. Cooking is a frequent behavior related to dietary activities at home. We hypothesized that "a parent cooking meals together with young children might alleviate dietary concerns." The aim of this study was to identify the relationship between parental cooking practices (e.g., cooking meals together with the child) and diet-related concerns. METHODS: Data were extracted from the "National nutrition survey on preschool children" conducted among nation-wide households with toddlers and preschoolers in 2015 by the Ministry of Health, Labour and Welfare of Japan. Parents were classified into two groups comprising those who cooked meals together with their children and those who did not. The following variables were compared: taking too much time to eat (slow eaters), "picky" eating (eating only certain foods), inconsistent food intake (eating too much or too little), playing with food/utensils while eating, preferring sweetened beverages and snacks over meals, eating too fast to chew well, not swallowing food, disinterested in eating, and spitting out food. The associations between parent-child cooking meals together and the concerns pertaining to the child's dietary habits and food intake were analyzed and compared between the two groups. RESULTS: The concerns of "picky eating" and "playing with food/utensils while eating" were lower, while "eating too much" was higher in the parent-cooking together group. The intake frequency of fish, soybeans/soy products, vegetables, and milk among children were higher in the "cooking together" group than among those in the "not cooking together" group. Children in the "cooking together" group consumed a significantly greater variety of foods than those in the "not cooking together" group. CONCLUSIONS: Cooking a meal together with a child may be related to the parent's lower concerns about the dietary habits of the child, including "picky eating" and "playing with food/utensils while eating," but may also be related to the higher concerns of "eating too much."

The trends in total energy, macronutrients and sodium intake among Japanese: findings from the 1995-2016 National Health and Nutrition Survey.

Monitoring nutritional status of the population is essential in the development and evaluation of national or local health policies. In this study, we aimed to demonstrate analysis on the trends in dietary intake of energy and macronutrients, as well as Na, in Japanese population using the data of series of cross-sectional national surveys - the National Nutrition Survey (NNS) and the National Health Nutrition Survey (NHNS) - during the period from 1995 to 2016. The NNS and NHNS participants aged 20-79 years were included in the analysis. Dietary intake was estimated using 1-d household-based dietary record. The trend in total energy intake, energy intake from macronutrients (fat and protein), Na intake and energy-adjusted Na intake were analysed using regression models adjusted to 2010 age distribution and anthropometry status. A total of 94 270 men and 107 890 women were included the analysis. Total energy intake showed a decreasing trend in both men and women. Similarly, energy intake from protein decreased, but energy intake (%) from fat increased in both sexes. Energy-adjusted Na intake showed a decreasing trend in both men and women. This study identified the decrease in total energy intake and energy intake from protein, whereas there were inverse trends in energy intake from fat among Japanese adults. Continued monitoring of trends in dietary intake will be needed, and there should be efforts to increase the accuracy of current survey procedures.

Impact of an education intervention focusing on comprehensive mindful eating and chewing habits on daily eating practices: A mobile tool-based randomized controlled trial.

BACKGROUND: Mindful eating (ME) emphasizes full awareness of food consumption, incorporating the practice of eating slowly. Traditional interventions targeting slower eating rates often concentrate on chewing behavior, leaving the impact of ME largely unexplored. The objective of this study was to evaluate the effectiveness of the ME program in improving eating rates and mindful eating compared to conventional education centered solely on chewing. METHODS: A total of 66 women university students were randomly assigned to either the ME (n = 33) or chewing intervention groups (n = 33). Education programs were delivered via smartphones over 8 weeks, with bi-weekly sessions where participants watched videos individually. The primary outcome was the eating rate, while the secondary outcome were eating style and the Mindful Eating Questionnaire (MEQ) assessed through web-based questionnaires. Measurements were taken pre-intervention, post-intervention, and at 1 and 3 months follow-up. Statistical analysis was conducted using intention-to-treat analysis. RESULTS: Both the ME and chewing groups showed slower eating rates compared to baseline, indicating the effect's temporal persistence, with no significant differences found between them at the end of the intervention and at 1 and 3 months post-intervention. In addition, the ME group significantly increased the MEQ scores compared to the chewing group. CONCLUSION: The educational program using ME reduced the rate of eating and achieved results similar to those of programs focused solely on chewing. Furthermore, it was effective in increasing MEQ scores. Based on these findings, a comprehensive education program that focuses on ME is recommended.

Development of a Reverse-Yield Factor Database Disaggregating Japanese Composite Foods into Raw Primary Commodity Ingredients Based on the Standard Tables of Food Composition in Japan.

The reverse-yield factor (RF) database was developed for qualitatively and quantitatively disaggregating Japanese composite foods into raw primary commodity (RPC) ingredients. Representative equations for four types (dried, salted, fermented and mixed foods) were developed to calculate RFs using the food content and composition data for composite foods listed in the Standard Tables of Food Composition in Japan-2020-(STFCJ), published by the Ministry of Education, Culture, Sports, Science and Technology of Japan. Out of 1150 composite foods identified in the STFCJ, RFs for 54 dried, 41 salted, 40 fermented and 818 mixed foods were obtained. RFs for 197 mixed foods could not be calculated because these foods were produced from ingredients with no specified information and/or through complex processing. The content and composition of Japanese composite foods would be interpreted representatively by RFs in the developed database.

Revised system to evaluate measurement of blood chemistry data from the Japanese National Health and Nutrition Survey and Prefectural Health and Nutrition Surveys.

BACKGROUND: We developed a monitoring system that uses total errors (TEs) to evaluate measurement of blood chemistry data from the National Health and Nutrition Survey (NHNS) and Prefectural Health and Nutrition Surveys (PHNS). METHODS: Blood chemistry data from the NHNS and PHNS were analyzed by SRL, Inc., a commercial laboratory in Tokyo, Japan. Using accuracy and precision from external and internal quality controls, TEs were calculated for 14 blood chemistry items during the period 1999-2010. The acceptable range was defined as less than the upper 80% confidence limit for the median, the unacceptable range as more than twice the cut-off value of the acceptable range, and the borderline range as the interval between the acceptable and unacceptable ranges. RESULTS: The TE upper limit for the acceptable and borderline ranges was 5.7% for total cholesterol (mg/dL), 9.9% for high-density lipoprotein cholesterol (mg/dL), 10.0% for low-density lipoprotein cholesterol (mg/dL), 10.4% for triglycerides (mg/dL), 6.6% for total protein (g/dL), 7.6% for albumin (g/dL), 10.8% for creatinine (mg/dL), 6.5% for glucose (mg/dL), 9.7% for γ-glutamyl transpeptidase (U/L), 7.7% for uric acid (mg/dL), 8.7% for urea nitrogen (mg/dL), 9.2% for aspartate aminotransferase (U/L), 9.5% for alanine aminotransferase (U/L), and 6.5% for hemoglobin A1c (%). CONCLUSIONS: This monitoring system was established to assist health professionals in evaluating the continuity and comparability of NHNS and PHNS blood chemistry data among survey years and areas and to prevent biased or incorrect conclusions.

[Epidemiological aspects of overweight and obesity in Japan--international comparisons].

Prevalence of obesity (BMI > or = 30) in Japanese adults (aged 20 years and over) was 3.8% in males and 3.2% in females (National Health and Nutrition Survey, 2010), being quite low compared with other countries listed in the Global Database on Body Mass Index (WHO). On the other hand, prevalence of overweight (BMI > or = 25) was 30.4% in males and 21.1% in females, of which overweight in males has increased in recent 35 years almost twice from 15% to 30%. Although the prevalence of overweight and obesity in Japanese adults is rather low in international comparisons, control for the obesity-associated risks through the promotion of appropriate body weight management has been prioritized in the national health programs.

Development of a Video-Based Tool for the Self-Assessment of Eating Rates in Young Adult Females.

Eating speed assessments are often based on self-reports, and establishing objective "ratings" is required to improve accuracy. However, no relevant simple assessment tool incorporating "ratings" is currently available. This study aimed to develop a group-adaptable eating rate assessment tool for young females using smartphones. Fifty female college students were directly observed while eating, and a self-assessment tool for the eating rate was created using video. Using the directly observed eating rate of a test food A as the gold standard (GS), we compared the eating rate self-assessment findings between those obtained using a conventional questionnaire and those obtained using an assessment tool. The validity and reproducibility of the assessment tool were verified. In terms of validity, the correlation coefficient for the GS questionnaire (r=0.442, p<0.001) was similar to that for the self-assessment tool (r=0.491, p<0.001). The reproducibility of repeated measurements of the self-assessment tool was inferior to that of the questionnaire (weighted kappa coefficients; 0.393 vs. 0.804). This may be explained in part by participants selecting the same items with specific words such as "fast" or "slow" on two occasions. As for the validity of test food A, additional measurements for test food C on a subset of subjects (n=16) showed a strong positive correlation (r=0.845, p<0.001) between A and C. The present study suggests that a video-based self-assessment tool we developed for young adult females is straightforward, and allows the subjects to observe specific and visual ratings in a manner that is less burdensome and time-effective than conventional questionnaire methods.

Validation of the most cost-effective nudge to promote workers' regular self-weighing: a cluster randomized controlled trial.

Regular self-weighing is useful in obesity prevention. The impact of nudge-based occupational self-weighing programs in the cluster randomized controlled trial was examined. The primary outcome was regular self-weighing after 6 months, which we used to compute cost-effectiveness. Participants were Japanese local government employees who underwent 1 h workshops after being assigned to one of the three nudge groups. Each group was designed according to the nudges' Easy, Attractive, Social, Timely framework: quiz group (n = 26, attractive-type nudges), implementation intentions group (n = 25, social-type nudges), and growth mindset group (n = 25, timely type nudges). A reference group (n = 36, no nudges) was also formed. After 6 months, all three interventions were effective for regular self-weighing, with the growth mindset intervention (60.0%) being significantly more effective. The cost-effectiveness of the growth mindset group was 1.7 times and 1.3 times higher than that of the quiz group and the implementation intentions group, respectively. Findings from our study are expected to facilitate the use of nudges for health practitioners and employers, which in turn may promote obesity prevention.

Internet use for health-related information via personal computers and cell phones in Japan: a cross-sectional population-based survey.

BACKGROUND: The Internet is known to be used for health purposes by the general public all over the world. However, little is known about the use of, attitudes toward, and activities regarding eHealth among the Japanese population. OBJECTIVES: This study aimed to measure the prevalence of Internet use for health-related information compared with other sources, and to examine the effects on user knowledge, attitudes, and activities with regard to Internet use for health-related information in Japan. We examined the extent of use via personal computers and cell phones. METHODS: We conducted a cross-sectional survey of a quasi-representative sample (N = 1200) of the Japanese general population aged 15-79 years in September 2007. The main outcome measures were (1) self-reported rates of Internet use in the past year to acquire health-related information and to contact health professionals, family, friends, and peers specifically for health-related purposes, and (2) perceived effects of Internet use on health care. RESULTS: The prevalence of Internet use via personal computer for acquiring health-related information was 23.8% (286/1200) among those surveyed, whereas the prevalence via cell phone was 6% (77). Internet use via both personal computer and cell phone for communicating with health professionals, family, friends, or peers was not common. The Internet was used via personal computer for acquiring health-related information primarily by younger people, people with higher education levels, and people with higher household incomes. The majority of those who used the Internet for health care purposes responded that the Internet improved their knowledge or affected their lifestyle attitude, and that they felt confident in the health-related information they obtained from the Internet. However, less than one-quarter thought it improved their ability to manage their health or affected their health-related activities. CONCLUSIONS: Japanese moderately used the Internet via personal computers for health purposes, and rarely used the Internet via cell phones. Older people, people with lower education levels, and people with lower household incomes were less likely to access the Internet via cell phone. The Internet moderately improved users' health-related knowledge and attitudes but seldom changed their health-related abilities and activities. To encourage communication between health providers and consumers, it is important to improve eHealth literacy, especially in middle-aged people. It is also important to make adequate amendments to the reimbursement payment system and nationwide eHealth privacy and security framework, and to develop a collaborative relationship among industry, government, and academia.

Maternal antenatal body mass index gains as predictors of large-for-gestational-age infants and cesarean deliveries in Japanese singleton pregnancies.

AIM: Greater antenatal weight or body mass index (BMI) gains may lead to larger fetuses and thus increase the risk for operative deliveries, such as cesarean deliveries. In order to examine the effect of weekly maternal weight and BMI changes on large-for-gestational-age (LGA) infants and cesarean delivery, delivery records from overall healthy women were analyzed. MATERIALS AND METHODS: Singleton, term delivery records from January to December 2003, at three obstetric departments (urban, suburban, rural) in Japan (1617 records) were analyzed. Multivariate logistic regression analyses were applied in order to estimate the effect of maternal pre-pregnancy body size, higher maternal weight or BMI gains by calculating the odds ratios for LGA infants and cesarean deliveries. RESULTS: Maternal pre-pregnancy overweight, primiparity, and BMI gains of more than 0.13 per week were independent factors positively related to LGA, and maternal underweight was negatively related. Urban hospital setting, maternal age 35 years or older, primiparity, and BMI gains of more than 0.13 per week independently increased the odds ratios for cesarean delivery. Weight or BMI gains between two-week intervals (26-28 weeks, 32-34 weeks) were not useful for predicting either LGA or cesarean delivery. LGA was unrelated to cesarean delivery risk. CONCLUSIONS: Applying BMI gains per week enables target weight gains to be set according to the mother's height, which may be useful in reducing risks for LGA and cesarean delivery, especially in shorter women. Further investigation may be needed to explore the practicality and effectiveness of advising women to gain weight according to their body height.

Mindful Eating Proficiency and Healthy Eating Literacy among Japanese Mothers: Associations with Their Own and Their Children's Eating Behavior.

Mindfulness is a process of focusing one's attention on the present moment. Applying this concept to eating (i.e., mindful eating (ME)) is associated with regulated eating behaviors, particularly in people with obesity and who are overweight. Sustaining healthy eating habits requires both healthy eating literacy (HEL) and proficiency in ME. However, ME proficiency in Japanese people has not been sufficiently investigated. In this paper, we conduct a survey of mothers with 4- to 5-year-old children in Aomori City, Japan, to investigate their ME proficiency and HEL level and eating behavior and self-reported body mass index in both mothers and their children from August to September 2019. This study is the first to describe ME proficiency in Japanese mothers. The study sample includes 128 participants from 18 nursery schools. ME proficiency in mothers was positively correlated with both their own and their children's eating behaviors, thereby suggesting a potential relationship, while strong relationships were not observed between the HEL level and eating behaviors of mothers and children. Improving ME skills, rather than HEL, may be an effective way to sustain healthier eating behaviors in mothers and their children. The level of evidence was Level V: Opinions of respected authorities based on descriptive studies, narrative reviews, clinical experience, or reports of expert committees.

[Dietary intake and health behavior in relation to total and disease-specific mortality in Japan: an ecological analysis].

PURPOSE: In order to improve population-based approaches in communities to extend healthy life expectancy of our population in the 21st century, it is essential to identify characteristics and risks thoroughly. This study assessed associations of dietary intake and health behavior with mortality from cancer, cardiovascular diseases, and all-causes in Japan at the prefectural level. METHODS: By prefecture and sex, we calculated age-adjusted means for BMI, step counts, and nutrient and food intakes, as well as age-adjusted prevalence of smoking and alcohol drinking habits, using datasets of the 2001-05 National Health and Nutrition Survey. Age-adjusted total mortality rates (per 100,000 population), as well as cancer and cardiovascular mortality rates were obtained from Vital Statistics (2007). Multivariate stepwise regression analysis was used to compute partial correlation coefficients. RESULTS: In regard to BMI, mortality from myocardial infarction and cerebral hemorrhage showed significant positive correlations in both males and females, but significant negative correlations with mortality from stomach cancer in both sexes. The sodium chloride equivalent (salt) was positively correlated with mortality from cerebral hemorrhage in both males and females. In males, salt was also positively correlated with total mortality. In females, salt was also positively correlated with mortality from cerebral infarction and all types of stroke. Alcohol drinking was positively correlated with mortality from esophageal cancer in both genders and from cerebral infarction in males. Several other nutrients and food groups, as well as physical activity, were also associated with mortality risk. CONCLUSIONS: Although this study is an ecological analysis, these findings highlight some factors of public health importance.

Association between Parent and Child Dietary Sodium and Potassium Intakes: Aomori Prefectural Health and Nutrition Survey, 2016.

This study investigated the association between parent and child sodium and potassium intakes using data from the 2016 Aomori Prefectural Health and Nutrition Survey. We analyzed one day dietary record data of 103 mothers, 94 fathers, 51 children aged 1-3 years, 39 children aged 4-6 years, 91 children aged 7-14 years, and 56 children aged 15-19 years. We also examined the association of sodium and potassium intake between co-habiting grandparents and their grandchildren. After adjusting for covariates, the total daily sodium intake in mothers was positively associated with that in children for every age group. Potassium intakes by the mothers during breakfast and dinner were positively associated with those in children aged 1-3, 4-6, and 7-14 years. The associations in sodium and potassium intakes between fathers and children were weaker. In addition, these associations were similar to those between the sodium intakes of grandchildren and their grandparents. The association between mother and child sodium and potassium intakes at breakfast and dinner was related to the consumption of similar foods, which suggests the importance of home environment in influencing total dietary sodium and potassium intake in Japanese people.

Seasonal changes in sleep duration and sleep problems: A prospective study in Japanese community residents.

BACKGROUND: A scientific understanding of the effects of seasonal changes on sleep duration and sleep problems such as insomnia and hypersomnia has yet to be elucidated; however, such an understanding could aid the establishment of an optimal sleep hygiene program to treat such problems. METHODS: We investigated the effects of seasonal changes on sleep duration and sleep problems in Japanese community residents. Data on 1,388 individuals aged 15-89 years who participated in the Survey of Seasonal Variations in Food Intakes conducted by the National Institute of Health and Nutrition of Japan (2004-2007) were analyzed. Participants completed a questionnaire including items on sleep duration and sleep problems (difficulty initiating sleep [DIS], difficulty maintaining sleep [DMS]/early morning awakening [EMA], and excessive daytime sleepiness [EDS]). Data were prospectively collected at four time points (spring, summer, fall, and winter). RESULTS: Seasonal changes in sleep duration were found, with the longest in winter and the shortest in summer (winter-summer difference: 0.19 h). The seasonality of sleep duration was influenced by age, sex, and residential area. In terms of age, seasonal changes in sleep duration were found in the middle and old age groups, but not in the young age group. Seasonal changes in the frequencies of sleep problems were found for some items in the young age group (DMS/EMA and EDS) and middle age group (DIS and DMS/EMA); however, no such changes were observed in the old age group. CONCLUSION: Seasonal effects on sleep and sleep problems were found in Japanese community residents, but these varied between age groups. Furthermore, seasonal changes in sleep duration were influenced by sex and residential area.