Short and long sleep duration and associated factors in pre-adolescence and early adulthood: evidence from the 1993 Pelotas birth cohort study.

OBJECTIVE: The objective of the present study was to investigate the associated factors with short and long sleep duration at ages 11 (pre-adolescence) and 22 years old (early adulthood). METHODS: Participants of the 1993 Pelotas birth cohort with self-reported sleep records at 11 (n = 4442) and 22 (n = 3800) years were included. The total sleep time duration was categorised as short (<9 h for 11 years and <7 h for 22 years), long (>11 for 11 years and >9 for 22 years) and recommended according to the National Sleep Foundation criteria. Multinomial regression analyses were applied according to a hierarchical approach in order to investigate the associated factors with sleep duration patterns. All analyses were stratified by sex. RESULTS: Higher income was associated with higher odds of short sleep duration in 11-year-old boys [OR = 1.54 (CI95%: 1.08; 2.19)] and girls [OR = 1.45 (CI95%: 1.03; 2.06)] and also with lower odds of long sleep duration in both ages. At 22 years, common mental health disorders were associated with higher odds of short sleep duration in both men [OR = 1.56 (CI95%: 1.18; 2.06)] and women [OR = 1.48 (CI95%: 1.11; 1.99)]. Sleep duration was also related to screen time and physical activity showing different association patterns according to sex and age. CONCLUSIONS: Different factors may be associated with sleep duration patterns in pre-adolescence and early adulthood. Our results emphasise the importance of considering stratification analyses to identify associated factors with sleep duration since they may vary according to age and sex.

Socioeconomic inequalities in the prevalence of underweight, overweight, and obesity among women aged 20-49 in low- and middle-income countries.

OBJECTIVE: To analyze socioeconomic inequalities in the prevalence of underweight and overweight or obesity in women from low and middle-income countries (LMICs). METHODS: Using the last available Demographic Health Survey between 2010 and 2016 from 49 LMICs, we estimated the prevalence of underweight (BMI < 18.5 kg/m2) and overweight or obesity combined (BMI ≥ 25 kg/m2) for women aged 20-49 years. We used linear regression to explore the associations between the two outcomes and gross national income (GNI). We assess within-country socioeconomic inequalities using wealth deciles. The slope index of inequality (SII) and the inequality pattern index (IPI) were calculated for each outcome. Negative values of the latter express bottom inequality (when inequality is driven by the poorest deciles) while positive values express top inequality (driven by the richest deciles). RESULTS: In total, 931,145 women were studied. The median prevalence of underweight, overweight or obesity combined, and obesity were 7.3% (range 0.2-20.5%), 31.5% (8.8-85.3%), and 10.2% (1.9-48.8%), respectively. Pearson correlation coefficients with log GNI were -0.33 (p = 0.006) for underweight, 0.72 (p < 0.001) for overweight or obesity, and 0.66 (p < 0.001) for obesity. For underweight, the SII was significantly negative in 38 of the 49 countries indicating a higher burden among poor women. There was no evidence of top or bottom inequality. Overweight or obesity increased significantly with wealth in 44 of the 49 countries. Top inequality was observed in low-prevalence countries, and bottom inequality in high-prevalence countries. CONCLUSION: Underweight remains a problem among the poorest women in poor countries, but overweight and obesity are the prevailing problem as national income increases. In low-prevalence countries, overweight or obesity levels are driven by the higher prevalence among the richest women; as national prevalence increases, only the poorest women are relatively preserved from the epidemic.