Maternal early pregnancy body mass index and risk of sleep apnea in the offspring.

STUDY OBJECTIVES: To investigate the association between maternal early pregnancy body mass index (BMI) and offspring sleep apnea diagnosis. METHODS: We conducted a nationwide cohort study among 3,281,803 singleton live births in Sweden born 1983-2015. Using national registers with prospectively recorded information, we followed participants for a sleep apnea diagnosis from 2 to up to 35 years of age. We compared sleep apnea risks by early pregnancy BMI categories using hazard ratios (HR) with 95% confidence intervals (CI) from adjusted Cox models. To address confounding by factors shared within families, we conducted sibling-controlled analyses and studied the relation of siblings' maternal BMI with index offspring's sleep apnea risk. RESULTS: There were 17,830 sleep apnea diagnoses. Maternal early pregnancy BMI was positively associated with offspring sleep apnea risk; compared with women with normal BMI (18.5-24.9), adjusted HR (95% CI) of offspring sleep apnea for maternal BMI categories 25.0-29.9 (overweight), 30.0-34.9 (obesity class I), and ≥35.0 (obesity class II or III) were, respectively, 1.14 (1.09, 1.19), 1.28 (1.20, 1.36), and 1.40 (1.27, 1.54). Corresponding HR from sibling-controlled analyses representing risk change for maternal BMI differences between pregnancies were, respectively, 1.13 (1.01, 1.26), 1.17 (0.97, 1.42), and 1.32 (0.97, 1.80). HR by siblings' maternal BMI were attenuated, suggesting a weak role for shared familial factors. Other pregnancy, birth, and neonatal complications were associated with offspring sleep apnea risk, but did not substantially mediate the association with maternal obesity. CONCLUSIONS: Maternal overweight and obesity are associated with offspring sleep apnea risk in a dose-response manner.

Sleep duration in middle childhood and age at menarche.

OBJECTIVE: Puberty affects sleep phasing. However, it is unclear if sleep duration earlier in childhood could influence the timing of pubertal events. We aimed to assess the association between middle childhood nighttime sleep duration and age at menarche (AAM). METHODS: In a cohort of 819 premenarcheal Colombian girls who were followed annually for the occurrence of menarche, we estimated adjusted hazard ratios (HR) with 95% confidence intervals (CI) for menarche by categories of recommended sleep duration in middle childhood using Cox models. Analyses were stratified by age at sleep assessment. RESULTS: Among girls aged 9 to <11 years, compared with girls who slept within recommendations, sleeping above recommendations was related to an adjusted 76% (95% CI: 4%, 198%; p = .04) higher probability of experiencing menarche during follow up. In girls aged ≥11 years, compared with girls who slept within recommendations, sleeping under recommendations was related to an adjusted 42% (95% CI: 5%, 93%; p = .03) higher probability of experiencing menarche during follow-up. Sleep duration was not associated with AAM in girls aged <9 years at the time of sleep assessment. CONCLUSIONS: Sleeping above recommendations in girls 9 to <11 years-old and sleeping under recommendations in girls ≥11 years-old is associated with earlier menarche.

Is the association of chronotype with adolescent behavior problems mediated through social jetlag?

We examined the associations of chronotype with behavior problems in a cross-sectional study of 957 Colombian adolescents (mean age, 14.6 years; 56% female), in addition to the mediating role of social jetlag. The midpoint of bedtime and waketime on free days, corrected for sleep debt accumulated during school week (MSFsc), was estimated from parent reports and used to assess chronotype. Behavior problems were evaluated through the Youth Self-Report (YSR) and the parent-completed Child Behavior Checklist (CBCL) questionnaires. We estimated adjusted mean differences with 95% CI in externalizing, internalizing, attention, social, and thought problem scores per one hour difference in chronotype using linear regression. Later chronotype was related to internalizing and externalizing behavior problems. Eveningness was associated with higher adjusted mean YSR scores (unit difference per hour) in externalizing behavior (1.0; 95% CI: 0.6, 1.5), internalizing behavior (0.6; 95% CI: 0.2, 1.1), attention problems (0.2; 95% CI: 0.0, 0.3), social problems (0.4; 95% CI: 0.1, 0.8), and thought problems (0.3; 95% CI: 0.1, 0.6). Similar patterns were observed with the CBCL. The associations of chronotype with somatic complaints and social problems were stronger in boys than they were in girls. Later chronotype was related to social jetlag but social jetlag was only associated with somatic complaints and attention problems, and mediated 16% and 26% of their corresponding associations with chronotype. In conclusion, later chronotype is associated with behavior problems in adolescence. Social jetlag does not substantially mediate these associations.

Middle childhood and adolescence sleep duration and behavior problems in adolescence.

We examined the associations of middle childhood and adolescence nighttime sleep duration with adolescence internalizing and externalizing behavior problems per the Youth Self-Report (YSR) and the Child Behavior Checklist (CBCL) questionnaires, in a cohort of 889 Colombian schoolchildren. We estimated adjusted differences with 95% confidence intervals (CI) in mean behavior problem t-scores in standardized units between recommended sleep duration categories and as a continuous exposure using multiple linear regression and restricted cubic spline models, respectively. Compared with sleep duration within recommendations, middle childhood sleep above recommendations was related to 4.6 (95% CI: 1.6, 7.6; p = .004) and 5.4 (95% CI: 1.2, 9.7; p = .01) adjusted units higher YSR and CBCL externalizing problem scores, respectively. In continuous exposure analyses, this association seemed restricted to children aged ≥11 years. Longer sleep, both in categories and as a continuous exposure, was also associated with increased CBCL internalizing problems. Results did not differ by sex or weekend/weekday sleep. Sleeping under recommendations in middle childhood was not significantly related to behavior problems; nevertheless, shorter sleep in adolescence, in both categorical and continuous scales, was significantly related to behavior problems. In conclusion, behavior problems in adolescence are associated with longer sleep in middle childhood and shorter sleep in adolescence.