Anne I. Wijtzes

Correlates of physical activity in 2-year-old toddlers: the generation R study.

OBJECTIVE To describe and identify correlates of objectively measured physical activity and sedentary behavior in 2-year-old toddlers. STUDY DESIGN A total of 347 children participating in a birth cohort study wore a unaxial ActiGraph accelerometer during 1 weekday and 1 weekend day. Information on potential correlates was assessed by parent-reported questionnaires, delivery reports, and regular visits to child health centers. Univariate and multivariable linear regression analyses were conducted to examine the associations between potential correlates and the following physical activity outcomes: percentage of time spent in sedentary behavior, percentage of time spent in moderate-to-vigorous physical activity, and mean counts per minute. RESULTS A high percentage of monitored time was spent in sedentary behavior; 85.6% on weekdays and 84.5% on weekend days. Four correlates were significantly associated with at least 1 physical activity outcome in the multivariable regression models: childs sex, childs age, number of siblings, and season of measurement. The associations of gross motor development with moderate-to-vigorous physical activity and mean counts per minute approached significance. Associations of socioeconomic variables and childs body mass index z-score with physical activity outcomes were not significant. CONCLUSION Two-year-old toddlers spend most of their time in sedentary behavior. No modifiable correlates were identified. Further research on physical activity and associated health benefits among very young children is warranted.

Overweight, Obesity and Underweight Is Associated with Adverse Psychosocial and Physical Health Outcomes among 7-Year-Old Children: The 'Be Active, Eat Right' Study

Background Limited studies have reported on associations between overweight, and physical and psychosocial health outcomes among younger children. This study evaluates associations between overweight, obesity and underweight in 5-year-old children, and parent-reported health outcomes at age 7 years. Methods Data were used from the ‘Be active, eat right’ study. Height and weight were measured at 5 and 7 years. Parents reported on child physical and psychosocial health outcomes (e.g. respiratory symptoms, general health, happiness, insecurity and adverse treatment). Regression models, adjusted for potential confounders, were fitted to predict health outcomes at age 7 years. Results The baseline study sample consisted of 2,372 children mean age 5.8 (SD 0.4) years; 6.2% overweight, 1.6% obese and 15.0% underweight. Based on parent-report, overweight, obese and underweight children had an odds ratio (OR) of 5.70 (95% CI: 4.10 to 7.92), 35.34 (95% CI: 19.16; 65.17) and 1.39 (95% CI: 1.05 to 1.84), respectively, for being treated adversely compared to normal weight children. Compared to children with a low stable body mass index (BMI), parents of children with a high stable BMI reported their child to have an OR of 3.87 (95% CI: 1.75 to 8.54) for visiting the general practitioner once or more, an OR of 15.94 (95% CI: 10.75 to 23.64) for being treated adversely, and an OR of 16.35 (95% CI: 11.08 to 24.36) for feeling insecure. Conclusion This study shows that overweight, obesity and underweight at 5 years of age is associated with more parent-reported adverse treatment of the child. Qualitative research examining underlying mechanisms is recommended. Healthcare providers should be aware of the possible adverse effects of childhood overweight and also relative underweight, and provide parents and children with appropriate counseling.

Development of socioeconomic inequalities in obesity among Dutch pre-school and school-aged children

To investigate the emergence of the inverse socioeconomic gradient in body mass index (BMI) in the first 6 years of life. Furthermore, associations of socioeconomic position (SEP) with BMI and total fat mass (%) were assessed at age 6, and potential mediating factors in the pathway between SEP and childrens body composition were investigated.

Genetic taste blindness to bitter and body composition in childhood: a Mendelian randomization design

Background:The ability to taste 6-n-propylthiouracil (PROP) may be associated with body composition, but previous findings from observational studies are conflicting and cannot be interpreted causally. The aim of this study was to estimate the causal association between PROP taster status and body composition in a population-based cohort study.Methods:The study was embedded in a population-based prospective birth cohort study. The TAS2R38 genotype (rs713598) was used as an instrumental variable (IV) to obtain unbiased effect estimates of the relation between PROP taster status and body weight (n=3778). Adiposity measures included body mass index (BMI) and fat mass measured by dual- energy X-ray absorptiometry scan at the child’s age of 6 years. Associations were investigated using both ordinary linear regression (OLS) and two-stage least squares regression (2SLS).Results:Non-taster girls had higher BMI standard deviation scores (SDS) and higher body fat as compared with taster girls (results from linear regression BMI SDS: –0.09, P=0.023, body fat mass (%): −0.49, P=0.028). The TAS2R38 genotype predicted PROP phenotype (F=240), indicating a strong IV. The 2SLS effect estimates were imprecise but similar to the observational estimates (−0.08 for BMI SDS and −0.46 for body fat mass %) and were not significantly different from the OLS results (Hausman test: P>0.10). For boys there were no differences observed between tasters and non-tasters.Conclusions:Our findings suggest a causal relation between PROP taster status and body weight among 6-year-old girls; Mendelian randomization was consistent with conventional estimates. In contrast, body weight among boys appeared to be independent of the PROP taster status. Further research should focus on possible underlying pathways, such as dietary behavior.

Sugar-containing beverage intake in toddlers and body composition up to age 6 years: The Generation R Study

Background/Objective:Intake of sugar-containing beverages (SCBs) has been associated with higher body mass index (BMI) in childhood. The potential effect of SCB intake during infancy is unclear. We examined the association of SCB intake at 13 months with BMI development until 6 years and body composition at age 6 years.Subjects/Methods:This study included 2371 Dutch children from a population-based prospective cohort study. SCB intake at 13 months was assessed using a Food Frequency Questionnaire with validation against 24-h recalls and was standardized for total energy. BMI was calculated from repeated weight and height measurements, and age- and sex-specific s.d. scores were calculated. Adiposity was measured using Dual-energy X-ray absorptiometry.Results:In girls, higher SCB intake at 13 months was significantly associated with higher BMI at ages 2, 3, 4 and 6 years (at age 6 years BMI (s.d. score) increase 0.11 (95% confidence interval (CI) +0.00; 0.23), high versus low intake). We observed a tendency towards higher android/gynoid fat ratio in girls with high intake (s.d. increase 0.14 (95% CI −0.02; 0.29), versus low intake) but not with body fat percentage. In boys, there was no association with BMI or body composition, but boys with high SCB intake at 13 months were taller at age 6 years (s.d. increase 0.14 (95% CI +0.00; 0.27), versus low intake).Conclusions:Higher SCB intake at 13 months was associated with higher BMI up to age 6 years in girls but not in boys. Our results imply that the unfavorable effects of SCB intake start early in life and that dietary advice regarding limiting SCB intake should already be given early in life.

Sedentary behaviors, physical activity behaviors, and body fat in 6-year-old children: The Generation R Study

BackgroundChildhood overweight and obesity is a major public health concern. Knowledge on modifiable risk factors is needed to design effective intervention programs. This study aimed to assess associations of children’s sedentary behaviors (television viewing and computer game use) and physical activity behaviors (sports participation, outdoor play, and active transport to/from school) with three indicators of body fat, i.e., percent fat mass, body mass index (BMI) standard deviation scores, and weight status (normal weight, overweight).MethodsCross-sectional data from 5913 6-year-old ethnically diverse children were analyzed. Children’s weight and height were objectively measured and converted to BMI. Weight status was defined according to age- and sex-specific cut-off points of the International Obesity Task Force. BMI standard deviation scores were created, based on Dutch reference growth curves. Fat mass was measured my dual-energy X-ray absorptiometry (DXA). Sedentary and physical activity behaviors were assessed by parent-reported questionnaires. Series of logistic and linear regression analyses were performed, controlling for confounders (i.e., socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors).ResultsSports participation was inversely associated with fat mass (p < 0.001), even after adjustment for socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors. No other independent associations were observed.ConclusionsThe results of this study indicate that sports participation is inversely associated with percent body fat among ethnically diverse 6-year-old children. More research in varied populations including objective measurements and longitudinal designs are needed to confirm these current results.

Preschool physical activity and functional constipation: The generation r study

Objectives: Decreased physical activity levels in children may partly explain the rising prevalence of functional constipation in childhood. The aim of the present study, therefore, was to examine the association between physical activity and functional constipation during the preschool period. Methods: This study was embedded in the Generation R study, a large prospective birth-cohort study in Rotterdam, The Netherlands. Physical activity was measured by an Actigraph accelerometer in 347 children (182 boys, 165 girls; mean age 25.1 months) and data were expressed as counts per minute. Data were categorized into light activity (302–614 counts/15 seconds), moderate activity (615–1230 counts/15 seconds), and vigorous activity (≥1231 counts/15 seconds). Functional constipation in the third and fourth year of life was defined according to the Rome II criteria. Results: Children spending time in the highest tertile of light (adjusted odds ratio [OR] 0.34; 95% confidence interval [CI] 0.13–0.87), moderate (adjusted OR 0.37; 95% CI 0.14–0.97), and total activity (adjusted OR 0.37; 95% CI 0.15–0.92) at the age of 2 years had significantly less functional constipation in the fourth year of life. For functional constipation in the third year of life, the results were in similar direction but not statistically significant. Additionally, children with physical activity of more than the WHO recommendation of 60 min/day had significantly less functional constipation in the fourth year of life (adjusted OR 0.48; 95% CI 0.24–0.97). Conclusions: Physical activity is associated with a decreased risk of functional constipation in the preschool period, but this may be time dependent.

Ethnic background and television viewing time among 4-year-old preschool children: the generation R study.

Objective: Childrens television viewing has been associated with an increased risk of overweight and obesity. This study aims to assess the associations of ethnic background and acculturation characteristics with television viewing time in 4-year-old preschool children. Method: The authors analyzed data from 3452 preschool children and their parents enrolled in the Generation R Study, a large, multiethnic, prospective birth cohort study in Rotterdam, the Netherlands. Multivariable logistic regression models were used to estimate odds ratios of watching television ≥2 hours/day and ≥1 hour/day for Turkish, Moroccan, and Surinamese children (reference group: native Dutch children), adjusted for family socioeconomic position. Effect modification by family socioeconomic position was also assessed. Results: After adjustment for family socioeconomic position, Turkish children (adjusted odds ratio [aOR], 2.27; 95% confidence interval [CI], 1.56–3.30), Moroccan children (aOR, 1.68; 95% CI, 1.03–2.76), and Surinamese children (aOR, 3.12; 95% CI, 2.16–4.50) were significantly more likely to watch television ≥2 hours/day compared with native Dutch children. Stratified analyses showed greater disparity between ethnic minority groups and native Dutch children at higher educational levels. There were no significant associations between acculturation characteristics (i.e., generational status, age at immigration, and Dutch language skills) and childrens television viewing time. Conclusion: Children from ethnic minority groups are at an increased risk for high levels of television viewing compared with native Dutch children, independent of family socioeconomic position. Interventions aimed to reduce television viewing time should target all children from ethnic minority groups.

Social Inequalities in Young Children’s Meal Skipping Behaviors: The Generation R Study

Background Regular meal consumption is considered an important aspect of a healthy diet. While ample evidence shows social inequalities in breakfast skipping among adolescents, little is known about social inequalities in breakfast skipping and skipping of other meals among young school-aged children. Such information is crucial in targeting interventions aimed to promote a healthy diet in children. Methods We examined data from 4704 ethnically diverse children participating in the Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Information on family socioeconomic position (SEP), ethnic background, and meal skipping behaviors was assessed by parent-reported questionnaire when the child was 6 years old. Multiple logistic regression analyses were performed to assess the associations of family SEP (educational level, household income, employment status, family composition) and ethnic background with meal skipping behaviors, using high SEP children and native Dutch children as reference groups. Results Meal skipping prevalence ranged from 3% (dinner) to 11% (lunch). The prevalence of meal skipping was higher among low SEP children and ethnic minority children. Maternal educational level was independently associated with breakfast skipping ([low maternal educational level] OR: 2.21; 95% CI: 1.24,3.94). Paternal educational level was independently associated with lunch skipping ([low paternal educational level] OR: 1.53; 95% CI: 1.06,2.20) and dinner skipping ([mid-high paternal educational level] OR: 0.39; 95% CI: 0.20,0.76). Household income was independently associated with breakfast skipping ([low income] OR: 2.43, 95% CI: 1.40,4.22) and dinner skipping ([low income] OR: 2.44; 95% CI: 1.22,4.91). In general, ethnic minority children were more likely to skip breakfast, lunch, and dinner compared with native Dutch children. Adjustment for family SEP attenuated the associations of ethnic minority background with meal skipping behaviors considerably. Conclusion Low SEP children and ethnic minority children are at an increased risk of breakfast, lunch, and dinner skipping compared with high SEP children and native Dutch children, respectively. Given these inequalities, interventions aimed to promote regular meal consumption, breakfast consumption in particular, should target children from low socioeconomic groups and ethnic minority children. More qualitative research to investigate the pathways underlying social inequalities in children’s meal skipping behaviors is warranted.

Early Sexual Intercourse : Prospective Associations with Adolescents Physical Activity and Screen Time

Objectives To assess the prospective associations of physical activity behaviors and screen time with early sexual intercourse initiation (i.e., before 15 years) in a large sample of adolescents. Methods We used two waves of data from the Rotterdam Youth Monitor, a longitudinal study conducted in the Netherlands. The analysis sample consisted of 2,141 adolescents aged 12 to 14 years (mean age at baseline = 12.2 years, SD = 0.43). Physical activity (e.g., sports outside school), screen time (e.g., computer use), and early sexual intercourse initiation were assessed by means of self-report questionnaires. Logistic regression models were tested to assess the associations of physical activity behaviors and screen time (separately and simultaneously) with early sexual intercourse initiation, controlling for confounders (i.e., socio-demographics and substance use). Interaction effects with gender were tested to assess whether these associations differed significantly between boys and girls. Results The only physical activity behavior that was a significant predictor of early sexual intercourse initiation was sports club membership. Adolescent boys and girls who were members of a sports club) were more likely to have had early sex (OR = 2.17; 95% CI = 1.33, 3.56. Significant gender interaction effects indicated that boys who watched TV ≥2 hours/day (OR = 2.00; 95% CI = 1.08, 3.68) and girls who used the computer ≥2 hours/day (OR = 3.92; 95% CI = 1.76, 8.69) were also significantly more likely to have engaged in early sex. Conclusion These findings have implications for professionals in general pediatric healthcare, sexual health educators, policy makers, and parents, who should be aware of these possible prospective links between sports club membership, TV watching (for boys), and computer use (for girls), and early sexual intercourse initiation. However, continued research on determinants of adolescents’ early sexual initiation is needed to further contribute to the strategies for improving adolescents’ healthy sexual development and behaviors.