Erica C. Jansen

Nutritional Determinants of the Timing of Puberty

The timing of puberty has important public health, clinical, and social implications. The plasticity of sexual development onset could be a mechanism that adapts to prevailing environmental conditions. Early-life nutrition may provide cues for the environments suitability for reproduction. This review focuses on recent developments in our understanding of the role of diet in the timing of sexual maturation. Population-based observational studies consistently indicate that childhood obesity is related to the earlier onset of puberty in girls. Similarly, intake of animal foods has been associated with earlier sexual development, whereas vegetable protein intake is related to delayed maturation. Evidence for prenatal nutrition, infant feeding practices, and childhood intake of fat, carbohydrate, and micronutrients is inconsistent. Secondary analyses of prenatal and early-life randomized nutritional interventions with extended follow-up through peripubertal years would help clarify the role of nutrition in the timing of sexual maturation.

Trends and correlates of age at menarche in Colombia: Results from a nationally representative survey

Surveillance of age at menarche could provide useful information on the impact of changing environmental conditions on child health. Nevertheless, nationally representative data are exceedingly rare. The aim of this study was to examine trends and sociodemographic correlates of age at menarche of Colombian girls. The study sample included 15,441 girls born between 1992 and 2000 who participated in the Colombian National Nutrition Survey of 2010. We estimated median menarcheal age using Kaplan-Meier time-to-event analyses. Hazard ratios with 95% confidence intervals were estimated with Cox regression models. The median age at menarche was 12.6 years. There was an estimated decline of 0.54 years/decade (P<0.001) over the birth years; this decline was only observed among girls from urban areas, and was more pronounced among girls from wealthier versus poorer families. Child height and BMI, maternal BMI and education, and family wealth were each inversely associated with menarcheal age whereas food insecurity and number of children in the household were positively associated with age at menarche. In conclusion, a negative trend in age at menarche is ongoing in Colombia, especially in groups most likely to benefit from socioeconomic development.

Age at menarche in relation to prenatal rainy season exposure and altitude of residence: Results from a nationally representative survey in a tropical country

Intrauterine exposure to the rainy season in the tropics may be accompanied by high rates of infection and nutritional deficiencies. It is unknown whether this exposure is related to the extrauterine timing of development. Our aim was to evaluate the relations of prenatal exposure to the rainy season and altitude of residence with age at menarche. The study included 15,370 girls 10 to <18 years old who participated in Colombias 2010 National Nutrition Survey. Primary exposures included the number of days exposed to the rainy season during the 40 weeks preceding birth, and altitude of residence at the time of the survey. We estimated median menarcheal ages and hazard ratios with 95% confidence interval (CI) according to exposure categories using Kaplan-Meier cumulative probabilities and Cox proportional hazards models, respectively. All tests incorporated the complex survey design. Girls in the highest quintile of gestation days exposed to the rainy season had an earlier age at menarche compared with those in the lowest (adjusted hazard ratios (HR)=1.08; 95% CI 1.00-1.18, P-trend=0.03). Girls living at altitudes ⩾2000 m had a later age at menarche compared with those living <1000 m (adjusted HR=0.88; 95% CI 0.82-0.94, P-trend <0.001). The inverse association between gestation days during the rainy season and menarche was most apparent among girls living at altitudes ⩾2000 m (P, interaction=0.04). Gestation days exposed to the rainy season and altitude of residence were associated with the timing of sexual maturation among Colombian girls independent of socioeconomic status and ethnicity.

Sociodemographic correlates and family aggregation of leukocyte telomere length in adults and children from Mesoamerica

Telomere length is a biomarker of cumulative stress and inflammation related to chronic disease risk. We examined the associations of leukocyte telomere length (LTL) with sociodemographic and anthropometric variables and estimated LTL family aggregation in Central America, a region with a high burden of chronic disease where LTL has not been studied.

Adiposity in Adolescents: The Interplay of Sleep Duration and Sleep Variability

Objective To assess whether adiposity measures differed according to joint categories of sleep duration and sleep variability in a sample of Mexican adolescents. Study design A sample of 528 Mexico City adolescents aged 9‐17 years wore wrist actigraphs for 6‐7 days. Average sleep duration was categorized as age‐specific sufficient or insufficient. Sleep variability, the standard deviation of sleep duration, was split at the median into stable versus variable. Adiposity measures—body mass index (BMI)‐for‐age Z score (BMIz), triceps skinfolds, waist circumference, and percent body fat—were collected by trained assistants. We regressed adiposity measures on combined sleep duration and variability categories. Log binomial models were used to estimate prevalence ratios and 95% CI for obesity (>2 BMIz) by joint categories of sleep duration and variability, adjusting for sex, age, and maternal education. Results Approximately 40% of the adolescents had insufficient sleep and 13% were obese. Relative to sufficient‐stable sleepers, adolescents with insufficient‐stable sleep had higher adiposity across all 4 measures (eg, adjusted difference in BMIz was 0.68; 95% CI, 0.35‐1.00) and higher obesity prevalence (prevalence ratio, 2.54; 95% CI, 1.36‐4.75). Insufficient‐variable sleepers had slightly higher BMIz than sufficient‐stable sleepers (adjusted difference, 0.30; 95% CI, 0.00‐0.59). Conclusions Adolescents with consistently insufficient sleep could be at greater risk for obesity. The finding that insufficient‐variable sleepers had only slightly higher adiposity suggests that opportunities for “catch‐up” sleep may be protective.

Key insomnia symptoms and incident pain in older adults: direct and mediated pathways through depression and anxiety

Pain is common among older adults and negatively impacts functioning. Sleep disturbances and mood disorders, specifically depression and anxiety, are closely associated with pain in older individuals, but the directionality of these associations remains unclear. In this study, we deconstruct long-term temporal effects of two key insomnia symptoms on incident pain into direct and indirect pathways, with focus on depression and anxiety symptoms, within a nationally representative sample. We utilized 2011-2013 data from the National Health and Aging Trends Study, a longitudinal survey of 2239 community-dwelling Medicare beneficiaries. Participants completed annual in-person interviews with assessments of sleep initiation and maintenance; depression, and anxiety (using the Patient Health Questionnaire-2 [PHQ-2] and the Generalized Anxiety Disorder Scale-2 [GAD-2] respectively); and bothersome pain. Causal mediation analysis was applied to examine direct effects of the two insomnia symptoms at baseline on incident pain, and their indirect effects through depression and anxiety symptoms. Almost one-third of the study participants were 69 years old or younger. A similar proportion reported bothersome pain in 2013. The two baseline insomnia symptoms predicted the development of pain. Adjusted analyses suggested that compared to older adults without the two baseline insomnia symptoms, participants with sleep initiation or maintenance difficulties had 24% (95% confidence interval [CI] 2%,51%) and 28% (95% CI 4%,55%) higher odds of incident pain, respectively. Anxiety symptoms partially mediated the relationship between the insomnia symptoms and incident pain, accounting for up to 17% of the total effect, but depressive symptoms did not. These results suggest that improved sleep or anxiety could reduce the risk for future pain.

Vegetable and lean proteins -based and processed meat and refined grains pattern -based dietary patterns in early childhood are associated with pubertal timing in a sex-specific manner: A prospective study of children from Mexico City

Childhood diet has been implicated in timing of sexual maturation. A key limitation of published studies is the focus on individual foods rather than patterns. We hypothesized that dietary patterns characterized by fruits and vegetables during early childhood (age 3 years) would be associated with delayed pubertal timing, whereas energy-dense and meat-based dietary patterns would relate to earlier puberty. The study population included 496 participants of a Mexico City birth cohort. The exposures of interest were dietary patterns derived from principal component analysis of dietary data collected via a semiquantitative food frequency questionnaire when the children were 3 years of age, and the outcomes were physician-assessed Tanner stages for pubic hair, breast (girls), genitalia, and testicular volume (boys) between 9 and 18 years, and initiation of menarche (girls). In regression analyses, we estimated adjusted hazard ratios and 95% confidence intervals for having reached Tanner stage ≥4 or initiation of menarche in girls and testicular volume ≥15 mL in boys. Among girls, those in the highest vs lowest tertile of vegetables and lean proteins pattern had a 35% (95% confidence interval 3%-67%) lower adjusted probability of having reached breast stage ≥4. Among boys, the processed meats and refined grain pattern score was associated with more advanced testicular development (adjusted hazard ratio = 3.58 [0.62-6.53]). Early childhood dietary patterns may play a role in the tempo of sexual maturation, which could ultimately carry implications for chronic disease susceptibility.

Sleep, Diet, and Cardiometabolic Health Investigations: a Systematic Review of Analytic Strategies

Purpose of ReviewPoor sleep is a risk factor for cardiometabolic morbidity. The relationship of sleep and cardiometabolic health could be confounded, mediated, or modified by diet, yet the incorporation of diet in sleep-cardiometabolic health studies is inconsistent. This rapid systematic literature review evaluates the conceptualization of diet as a confounder, mediator, or effect modifier within sleep-cardiometabolic health investigations, and the statistical approaches utilized.Recent FindingsOf 4692 studies identified, 60 were retained (28 adult, 32 pediatric). Most studies included diet patterns, quality, or energy intake as confounders, while a few examined these dietary variables as mediators or effect modifiers. There was some evidence, mostly in pediatric studies, that inclusion of diet altered sleep-cardiometabolic health associations.SummaryDiet plays a diverse role within sleep-cardiometabolic health associations. Investigators should carefully consider the conceptualization of diet variables in these relationships and utilize contemporary statistical approaches when applicable.

Sleep and Gastrointestinal Symptoms in a Community-Based Survey of Children:

We examined whether gastrointestinal (GI) symptoms were associated with sleep disturbances in a community-based sample of 337 school-aged children from Ypsilanti, Michigan. Parents completed the sleep-related breathing disorder scale of the Pediatric Sleep Questionnaire and the Conners’ parents rating scale, which included questions concerning GI symptoms. One fifth of the children screened positive for sleep-disordered breathing; the same fraction had sleepiness, and one-quarter snored more than half the time. Similarly, one quarter of children had 2 or more GI symptoms. Children with positive sleep-disordered breathing scores were 2.22 times as likely to have 2 or more GI symptoms in the past month after confounder adjustment (95% confidence interval = 1.39-3.55). In particular, this relationship appeared to be driven by daytime sleepiness, as children with sleepiness had about a 2-fold higher prevalence of 2 or more GI symptoms (adjusted prevalence ratio = 1.96, 95% confidence interval = 1.18-3.26). Neither snoring nor sleep duration were associated with GI symptoms.