A tendency toward evening chronotype associates with less healthy diet among preschoolers: cross-sectional findings from the DAGIS study

Study Objectives

Evidence suggests that adolescents and adults with a later chronotype have poorer sleep habits and are more susceptible to unhealthy behaviors, but little is known about these associations in younger children. The objective of the study was to (1) identify and compare individual chronotype tendencies among preschool-aged children and (2) investigate associations of sleep dimensions and chronotype with diet.

Methods

Participants were 636 3-6 years old (mean ± SD age: 4.74 ± 0.89 years, 49% girls) preschoolers from the cross-sectional Increased Health and Well-Being in Preschoolers (DAGIS) study in Finland. Sleep duration, sleep variability (in duration and midpoint), social jetlag, and midsleep on weekends adjusted for sleep debt (MSWEadj) were measured with 7-day actigraphy. Morning, intermediate, and evening chronotype tendencies were defined based on the lowest and highest 10th percentile cutoffs of MSWEadj. Food, energy, and macronutrient intake were assessed from 3-day records. Associations between sleep dimensions and diet were assessed with regression models.

Results

MSWEadj was 1:13 ± 14 minutes for morning (n = 64), 2:25 ± 28 minutes for intermediate (n = 560), and 3:38 ± 15 minutes for evening (n = 64) chronotype tendency. Children with an evening chronotype tendency had greater social jetlag and sleep variability. Having an evening chronotype tendency was associated with higher added sugar, higher sugary food consumption, and lower vegetable consumption compared to intermediate tendency types. A later chronotype (MSWEadj) was associated with higher sugary food consumption, as well as lower vegetable and fiber intake. Sleep duration, social jetlag, and sleep variability were not associated with diet.

Conclusions

Several less healthy sleep and diet behaviors were observed among children with later chronotypes. Future public health interventions aimed towards children would benefit from taking into account chronotype.

Food consumption and nutrient intake of Finnish preschool children according to parental educational level

We examined the association between parental educational level (PEL) and children's food consumption and nutrient intake in a sample of Finnish 3- to 6-year-old preschoolers (n 811). The data were obtained from the cross-sectional DAGIS project, conducted in eight municipalities in Finland during 2015-2016. The food consumption and nutrient intake were assessed using food records. The highest educational level of the family was used as the indicator of socio-economic status. Differences in diet by PEL were analysed using a hierarchical linear model adjusted for energy intake. Compared with high PEL, low PEL was associated with a child's lower consumption of fresh vegetables and salads, vegetarian dishes, berries, white bread, blended spread, skimmed milk and ice cream but higher consumption of milk with 1-1·5 % fat content, dairy-based desserts and sugar-sweetened soft drinks. Food consumption was also examined after disaggregating dishes into their ingredients. Low PEL was associated with lower consumption of vegetables, nuts and seeds, berries and fish but higher consumption of red meat. Children in the low PEL, compared with the high PEL group, had a lower intake of protein, fibre, EPA, DHA, vitamin D, riboflavin, vitamin B6, folate, vitamin B12, vitamin C, potassium, phosphorous, Ca, Mg, Zn and iodine but a higher intake of fat and saturated, trans and MUFA. The observed diet-related disparities highlight the need for policy actions and interventions supporting healthy eating patterns such as high consumption of vegetables, nuts and berries in childhood, paying special attention to those with low PEL.

Child temperament is associated with energy intake and its day-to-day variability among preschoolers-Results from a cross-sectional DAGIS study

BACKGROUND

Although research has linked children's temperament with weight outcomes, the associations between temperament and dietary outcomes, particularly energy intake, remain understudied. Furthermore, little is known about how temperament is associated with diet in the early childhood education and care (ECEC) context, which is an important environment for many children.

OBJECTIVES

This study examined whether temperament is associated with mean energy intake and its day-to-day variability. In addition, the associations were examined separately in the contexts of home and ECEC.

METHODS

The study used data from 505 Finnish children from a cross-sectional DAGIS study conducted in 2015-2016. Parents reported their child's temperament with a questionnaire and food consumption with a food record for two weekdays (outside daycare hours) and one weekend day. Early educators at an ECEC centre reported the child's food consumption during the daycare hours on the same weekdays as the parents kept food records at home. Associations were examined with linear regression models.

RESULTS

Children with higher surgency had a higher mean daily energy intake. When examined separately at home and in the ECEC centre, the association was found only in the ECEC centre. Children with higher negative affectivity had greater day-to-day variability in energy intake. This association, however, was not observed when examined separately at home and at the ECEC centre.

CONCLUSIONS

The results indicate that temperament may shape children's energy intake. Moreover, the role of the ECEC context in children's eating may be different depending on a child's temperamental dispositions, which warrants further research.

Is parental socioeconomic status associated with irregularity of energy intake among children?

Background

The timing of eating, chrono-nutrition, is a relatively new research area, where the focus is not on only what we eat but also when we eat and of irregularity between days. Chrono-nutrition have been associated with cardiovascular risk factors among adults. Societal factors influence the chrono-nutrition, but there is limited research on how different socioeconomic factors are associated with chrono-nutrition, especially among children. The aim of this study is to examine the association between parental socioeconomic status and irregularity of children’s energy intake.

Methods

We used data from the DAGIS (Increased Health and Wellbeing in Preschools) study in years 2015-2016, in which 864 preschool children participated (age 3-6 years old). Childreńs dietary intake was measured by a 3-day food record. We included only children that had complete data from all three days and the child was at day care on two of those days and one day was a weekend day (n = 568). To calculate the irregularity score, the absolute difference between the daily energy intake and 3-day mean intake for each three days was divided by the 3-day mean energy intake, multiplied by 100 and then averaged over the 3 days; this served as a measure of irregularity of energy intake, with a low score indicating a more regular energy intake and a higher more irregular energy intake. The parents reported highest parental educational level and household income on a questionnaire. The associations were tested by general linear models on SPSS.

Results

No association was found between parental educational level or household income with irregularity of children’s energy intake.

Conclusions

There was no association between parental socioeconomic status and children’s irregularity of energy intake. Other aspects of children’s chrono-nutrition should also be tested to be able to conclude that children’s chrono-nutrition is not influenced by parental socioeconomic status.

Key messages

• We found no association between parental socioeconomic status and irregularity in children’s energy intake.

• Chrono-nutrition among children is under-examined.

Preschool children’s temperament and its associations with energy intake

Background and objectives

Child's temperament dimensions have been linked with different weight outcomes as well as dietary factors such as consumption of fruit and vegetables, sugar-rich foods and drinks and an overall dietary quality. Links between temperament dimensions and energy intake, however, remain under-examined. This study expands the literature by investigating associations between child's temperament dimensions and energy intake.

Methods

Altogether 505 Finnish children aged 3-6 years provided data for the analyses. The data is a part of the DAGIS (Increased Health and Wellbeing in Preschools) study conducted in 2015-2016. Child's energy intake was measured with 3-day food records. To be included, children had to 1) have food record for two preschool days and one weekend day and 2) to have consumed both lunch and an afternoon snack in the preschool on the two preschool days. The very short form of Children's Behavior Questionnaire was used to measure child's temperament dimensions. Concurrent associations between three temperament dimensions (surgency, negative affectivity, and effortful control) and energy intake were examined using linear regression models adjusted for child's age, sex, mother's highest education, and moderate-to-vigorous physical activity.

Results

Surgency, temperament dimension referring to characteristics such as impulsivity, high activity level and high approach, was positively associated with energy intake. Effortful control or negative affectivity were not associated with energy intake.

Conclusions

The findings imply that temperamental surgency may be one relevant determinant of energy intake among preschool children. The result is in line with previous studies linking child's surgency as well as its specific facets, such as impulsivity, with weight outcomes and food approach behaviors. Considering child's individual temperament dimensions when counselling families in eating issues could be beneficial.

Key messages

• Surgency, a temperament dimension referring to characteristics such as impulsivity, high activity level and high approach, was positively associated with energy intake.

• When promoting children’s balanced eating, tailored support for parents acknowledging child’s temperament could be beneficial.

Does temperament make children differently susceptible to their home physical food environment? A cross-sectional DAGIS study on 3-6 year old Finnish children's food consumption

Consistently linked with children's food consumption are food availability and accessibility. However, less is known about potential individual differences among young children in their susceptibility to home food environments. The purpose of the study was to examine whether the association between home food availability and accessibility of sugar-rich foods and drinks (SFD) or fruits and vegetables (FV) and children's consumption of these foods differ according to their temperament. The study used two cross-sectional datasets collected as part of the Increased Health and Wellbeing in Preschools (DAGIS) study: 1) a cross-sectional data of 864 children aged 3-6 years old collected between fall 2015 and spring 2016, and 2) an intervention baseline data of 802 children aged 3-6 collected in fall 2017. Parents reported their children's temperament, consumption of FV and SFD, and home availability and accessibility of SFD and FV. Examination of whether associations between home availability and accessibility of FV and their consumption differ according to children's temperament involved using linear regression models. Similar models were used to examine association between home availability and accessibility of SFD and their consumption, and the moderating role of temperament. The association between home accessibility of SFD and their consumption frequency was dependent on the level of children's negative affectivity. More frequent consumption of SFD was observed with higher home accessibility of SFD. The association was stronger in children with higher scores in negative affectivity. No other interactions were found. Children with higher negative affectivity are possibly more vulnerable to food cues in the home environment than children with lower negative affectivity. Consideration of children's individual characteristics is necessary in supporting their healthy eating.

Do stressed children have a lot on their plates? A cross-sectional study of long-term stress and diet among Finnish preschoolers

We examined the association between hair cortisol concentration (HCC) - an indicator of long-term stress - and diet among preschoolers in a cross-sectional design. The participants were 597 Finnish 3-6-year-olds, and the data were collected in 2015-16. We used 4-cm hair samples to analyze HCC during the past four months. Food consumption was assessed using a food frequency questionnaire, and we used consumption frequencies of selected food groups as well as data-driven dietary pattern scores in the analyses. The parents of the participating children reported their educational level and family income. The researchers measured the children's weight and height. We examined the associations between HCC and diet using multilevel linear mixed models adjusted for age, gender, the highest education in the family, household relative income, and child BMI. Higher HCCs were associated with less frequent consumption of fruit and berries (B estimate -1.17, 95% CI -2.29, -0.05) and lower scores in a health-conscious dietary pattern (B estimate -0.38, 95% CI -0.61, -0,14). Higher HCCs were also associated with more frequent consumption of sugary beverages (B estimate 1.30, 95% CI 0.06, 2.54) in a model adjusted for age, gender and highest education in the family, but the association attenuated after further adjustments. Our results are parallel with previous studies that show a link between stress and unhealthy diet. In the future, longitudinal studies are needed to establish a causal relationship between stress and diet among children.

Children’s food intake in relation to preschool-level facilitators and barriers of healthy nutrition

Background

Childcare is an important setting for young children’s food consumption as, in Finland, most children eat three meals a day in childcare. Thus, it is important to recognize determinants of children’s dietary intake in childcare. The aim of this study was to examine food-related factors at preschool and manager-level and their association with children’s fruit, vegetable and fibre intake at preschool.

Methods

The study was a part of the cross-sectional DAGIS survey conducted in 2015-2016. It aimed to examine 3-6-year-old preschoolers’ energy balance-related behaviors in Finland. Preschool managers from 58 preschools filled in a questionnaire on food and nutrition related factors at preschool such as kitchen type, food policies, food education, the manager’s possibilities to impact fruit and vegetable supply and cooperation challenges with the catering service. Preschool personnel kept food record for the children (n = 585) on two preschool days. Multilevel linear and logistic regression analyses were conducted with age, gender and municipality as confounders, preschool-level factors as independent variables and children’s vegetable (g/day) and fruit (yes vs. no) consumption, and fibre intake (g/MJ) as outcome variables.

Results

Having many written food policies in the preschool was associated with higher intake of vegetables (p = 0.01) and fibre (p = 0.03) among the children. Having at least 2 out of 3 different cooperation challenges with the catering service was associated with higher intake of fibre (0.03) and lower odds of eating fruits (p = 0.01).

Conclusions

Written food policies and manager-reported challenges with the catering service were associated with children’s vegetable, fruit and fiber intake at preschool. Factors that are relatively distal from the meal situations may impact children’s food intake at preschool and should be taken into account when promoting healthy food intake at preschool, but more studies are needed.

Key messages

Written food policies and good cooperation between the preschool and catering services may be of benefit to children’s healthy food intake at preschool. The relation between preschool and manager-level factors and children’s food intake are very little studied, and thus more studies are needed before conclusions can be made.

Fruit, Vegetable, and Fibre Intake among Finnish Preschoolers in Relation to Preschool-Level Facilitators and Barriers to Healthy Nutrition

Preschool is a major factor affecting food consumption among young children in Finland, given that most preschoolers eat three meals a day in that setting. Thus, it is important to recognise the determinants of dietary intake at preschool. The aim of this study was to examine food-related factors at the preschool and manager level, and their association with the dietary intake of children in childcare. The study was a part of the cross-sectional DAGIS survey conducted in 2015 to 2016 in Finland. The managers of 58 preschools filled in a questionnaire related to food and nutrition at their preschools. Preschool personnel kept food records for the children (n = 585) on two preschool days. Multilevel linear and logistic regression analyses were conducted with age, gender, and municipality as covariates, preschool-level factors as independent variables, and children's vegetable (g/day) and fruit (yes vs. no) consumption and fibre intake (g/MJ) as outcome variables. Having many written food policies in the preschool was associated with a higher intake of vegetables (p = 0.01) and fibre (p = 0.03) among the children. Having at least two out of three cooperation-related challenges with the catering service was associated with a higher intake of fibre (p = 0.03) and lower odds of eating fruit (p = 0.01). Factors that are relatively distal from meal situations may have an effect, and should be taken into account in the promotion of healthy eating at preschool, but more studies are needed.

Neighborhood Socioeconomic Status and Feeding Practices in Finnish preschools

Aims: Certain feeding practices, such as role modeling healthy eating and encouragement are recommended to be used in preschools. Little is known about whether preschool characteristics are associated with the use of these feeding practices. Our aim was to examine whether the socioeconomic status (SES) of the preschool neighborhood is associated with the feeding practices in preschools. Methods: This study was part of the cross-sectional DAGIS study. We studied 66 municipal preschools and 378 early childhood educators (ECEs). Preschool neighborhood SES was assessed with map grid data. Feeding practices were assessed by questionnaires and lunchtime observation. Associations between preschool neighborhood SES and feeding practices were tested with logistic regression analyses adjusted for ECEs' educational level and municipal policies on ECEs' lunch prices, and on birthday foods. Results: The crude model showed that in high-SES neighborhood preschools ECEs were more likely to eat the same lunch as the children (OR 2.46, 95% CI 1.42-4.24) and to reward children with other food for eating vegetables (OR 2.48, 95% CI 1.40-4.41). Furthermore, in high-SES preschools it was less likely that birthday foods outside of the normal menu were available on birthdays (OR 0.29, 95% CI 0.12-0.71). In the adjusted model, rewarding with other food remained associated with preschool neighborhood SES (OR 2.13, 95% CI 1.12-4.07). Conclusions: After adjustments, preschool neighborhood SES was mostly unassociated with the feeding practices in preschools. Municipal policies may have a significant impact on feeding practices and ultimately on young children's food intake in Finland where most children attend municipal preschools.

Interannual variation in UV-B and temperature effects on bud phenology and growth in Populus tremula

Warming affects phenological processes such as spring bud break and autumnal bud set, and also growth rates of trees. Recently, it has been shown that these physiological processes also may be influenced by the ultraviolet-B (UV-B) part of the solar spectrum, and there are reasons to expect that the two environmental factors induce interactive effects when acting in concert. In this study, our aim was to elucidate how experimental enhancements in temperature and UV-B, alone and in combination, affect growth and seasonal phenology of Eurasian aspen (Populus tremula) over several growing seasons (three years). Moreover, we tested how environmentally induced changes in phenology affect the growth achieved over each season, that is, the importance of a prolonged growing season for growth yield. The plants grew in an outdoor experiment with modulated enhancements of temperature and UV-B during the growing season. Both UV-B and temperature enhancement affected bud set dates, while bud break dates were only affected by temperature enhancement. Temperature delayed bud set in all years, but gradually less over years, while UV-B yielded earlier bud set the first year but showed a delayed response the following years. Bud break was always earlier under temperature enhancement. The experimentally induced extension of the growing season in both ends had a positive effect of growth throughout the three-year period. However, the reduced responsiveness of bud set to both enhancement treatments suggest that the plants gradually acclimated to the modified climate, a finding that should also be investigated for other tree species.

Increased Health and Wellbeing in Preschools (DAGIS) Study-Differences in Children's Energy Balance-Related Behaviors (EBRBs) and in Long-Term Stress by Parental Educational Level

This paper describes the Increased Health and Wellbeing in Preschools (DAGIS) survey process and socioeconomic status (SES) differences in children's energy balance-related behaviors (EBRBs), meaning physical activity, sedentary and dietary behaviors, and long-term stress that serve as the basis for the intervention development. A cross-sectional survey was conducted during 2015⁻2016 in 66 Finnish preschools in eight municipalities involving 864 children (3⁻6 years old). Parents, preschool personnel, and principals assessed environmental factors at home and preschool with questionnaires. Measurement of children's EBRBs involved three-day food records, food frequency questionnaires (FFQ), seven-day accelerometer data, and seven-day sedentary behavior diaries. Children's long-term stress was measured by hair cortisol concentration. Parental educational level (PEL) served as an indicator of SES. Children with low PEL had more screen time, more frequent consumption of sugary beverages and lower consumption of vegetables, fruit, and berries (VFB) than those with high PEL. Children with middle PEL had a higher risk of consuming sugary everyday foods than children with high PEL. No PEL differences were found in children's physical activity, sedentary time, or long-term stress. The DAGIS intervention, aiming to diminish SES differences in preschool children's EBRBs, needs to have a special focus on screen time and consumption of sugary foods and beverages, and VFB.

The benefits of interpopulation hybridization diminish with increasing divergence of small populations

Interpopulation hybridization can increase the viability of small populations suffering from inbreeding and genetic drift, but it can also result in outbreeding depression. The outcome of hybridization can depend on various factors, including the level of genetic divergence between the populations, and the number of source populations. Furthermore, the effects of hybridization can change between generations following the hybridization. We studied the effects of population divergence (low vs. high level of divergence) and the number of source populations (two vs. four source populations) on the viability of hybrid populations using experimental Drosophila littoralis populations. Population viability was measured for seven generations after hybridization as proportion of populations facing extinction and as per capita offspring production. Hybrid populations established at the low level of population divergence were more viable than the inbred source populations and had higher offspring production than the large control population. The positive effects of hybridization lasted for the seven generations. In contrast, at the high level of divergence, the viability of the hybrid populations was not significantly different from the inbred source populations, and offspring production in the hybrid populations was lower than in the large control population. The number of source populations did not have a significant effect at either low or high level of population divergence. The study shows that the benefits of interpopulation hybridization may decrease with increasing divergence of the populations, even when the populations share identical environmental conditions. We discuss the possible genetic mechanisms explaining the results and address the implications for conservation of populations.

Predominance of outcrossing in Lymnaea stagnalis despite low apparent fitness costs of self-fertilization

We have quantified the natural mating system in eight populations of the simultaneously hermaphroditic aquatic snail Lymnaea stagnalis, and studied the ecological and genetic forces that may be directing mating system evolution in this species. We investigated whether the natural mating system can be explained by the availability of mates, by the differential survival of self- and cross-fertilized snails in nature, and by the effects of mating system on parental fecundity and early survival. The natural mating system of L. stagnalis was found to be predominantly cross-fertilizing. Density of snails in the populations had no relationship with the mating system, suggesting that outcrossing rates are not limited by mate availability at the population densities observed. Contrary to expectations for outcrossing species, we detected no evidence for inbreeding depression in survival in nature with inferential population genetic methods. Further, experimental manipulations of mating system in the laboratory revealed that self-fertilization had no effect on parental fecundity, and only minor effects on offspring survival. Predominance of cross-fertilization despite low apparent fitness costs of self-fertilization is at odds with the paradigm that high self-fertilization depression is necessary for maintenance of cross-fertilization in self-compatible hermaphrodites.