Childhood obesity: evidence for distinct early and late environmental determinants a 12-year longitudinal cohort study (EarlyBird 62)

Body Mass Index Trajectory and Incident Hypertension: Results From a Longitudinal Cohort of Chinese Children and Adolescents, 2006-2016

Objectives. To identify body mass index (BMI) trajectories in Chinese children and to compare the risk of incident high blood pressure (HBP) across trajectory groups.Methods. A total of 9286 children were included. The mean age at baseline was 8.9 years; age at endpoint ranged between 16 and 18 years. At least 8 measurements were obtained from each involved child. We used group-based trajectory modeling to identify BMI trajectory groups in each sex. We used blood pressure from each measurement to define HBP.Results. We identified 4 BMI trajectories for each sex. Compared with the low trajectory group, the hazard ratios of HBP in the higher trajectory groups ranged from 1.17 (95% confidence interval [CI] = 1.11, 1.23) to 2.00 (95% CI = 1.78, 2.27) during follow-up, and HBP risk at late adolescence ranged from 1.36 (95% CI = 1.22, 1.52) to 3.63 (95% CI = 3.12, 4.21). All trend P values across trajectories were less than .001. In terms of population level, overweight started 3 years earlier than HBP.Conclusions. Children of higher BMI trajectories had a higher risk of HBP during adolescence. The transition period from overweight to HBP onset could be critical for HBP prevention.

Calorie Restriction Modulates Reproductive Development and Energy Balance in Pre-Pubertal Male Rats

The objective was to determine effects of feed restriction and refeeding on reproductive development and energy balance in pre-pubertal male rats. Sprague Dawley rats (n = 32, 24 days old, ~65 g), were randomly allocated into four treatments (n = 8/treatment): (1) Control (CON, ad libitum feed; (2) Mild Restriction (MR, rats fed 75% of CON consumption); (3) Profound Restriction (PR, 50% of CON consumption); or (4) Refeeding (RF, 50% restriction for 14 days, and then ad libitum for 7 days). Feed restriction delayed reproductive development and decreased energy balance and tissue accretion, with degree of reproductive and metabolic dysfunctions related to restriction severity. In RF rats, refeeding largely restored testis weight, sperm production (per gram and total), plasma IGF-1, leptin and insulin concentrations and energy expenditure, although body composition did not completely recover. On Day 50, more CON and RF rats than PR rats were pubertal (5/6, 4/5 and 1/6, respectively; plasma testosterone >1 ng/mL) with the MR group (4/6) not different. Our hypothesis was supported: nutrient restriction of pre-pubertal rats delayed reproductive development, induced negative energy balance and decreased metabolic hormone concentrations (commensurate with restriction), whereas short-term refeeding after profound restriction largely restored reproductive end points and plasma hormone concentrations, but not body composition.

Post-2000 growth trajectories in children aged 4-11 years: A review and quantitative analysis

Children's body mass index (BMI) growth trajectories are associated with adult health outcomes, and vary by geography and epoch. Understanding these trajectories could help to identify high risk children and thus support improved health outcomes. In this review, we compare and quantitatively analyse BMI level and trajectory data published since 2010. We characterise recent growth in children aged 4-11 years, an age range most frequently targeted for BMI intervention, yet less studied than young childhood or infancy. Through searches in OVID, we identified 54 relevant texts which describe either post-2000 summary BMI values by age and gender in cohorts with sample sizes of over 1000 children, or the results of latent class analyses of BMI trajectories within the 4-11 year age range. Population level median growth curves were projected and visualised as weighted means. These BMI curves, based on data from 729,692 children, can be visually clustered into 'high' and 'low' charting groups with extreme outlying values. Within populations, latent class analyses converge on 3-4 individual child trajectories, two of which predispose adult overweight. These growth pathways diverge early in childhood, yet are not effectively distinguished via isolated BMI measurements taken between 4 and 11 years, meaning some high risk children may currently be poorly identified.

Identifying County-Level All-Cause Mortality Rate Trajectories and Their Spatial Distribution Across the United States

INTRODUCTION

All-cause mortality in the United States declined from 1935 through 2014, with a recent uptick in 2015. This national trend is composed of disparate local trends. We identified distinct groups of all-cause mortality rate trajectories by grouping US counties with similar temporal trajectories.

METHODS

We used all-cause mortality rates in all US counties for 1999 through 2016 and estimated discrete mixture models by using county level mortality rates. Proc Traj in SAS was used to detect how county trajectories clustered into groups on the basis of similar intercepts, slopes, and higher order terms. Models with increasing numbers of groups were assessed on the basis of model fit. We created county-level maps of mortality trajectory groups by using ArcGIS.

RESULTS

Eight unique trajectory groups were detected among 3,091 counties. The average mortality rate in the most favorable trajectory group declined 29.4%, from 592.3 deaths per 100,000 in 1999 to 418.2 in 2016. The least favorable mortality trajectory group declined 3.4% over the period, from 1,280.3 deaths per 100,000 to 1,236.9. We saw significant differences in the demographic and socioeconomic profiles and geographic patterns across the trajectory categories, with favorable mortality trajectories in the Northeast, Midwest, and on the West Coast and unfavorable trajectories concentrated in the Southeast.

CONCLUSIONS

County-level disparities in all-cause mortality rates widened over the past 18 years. Further investigation of the determinants of the trajectory groupings and the geographic outliers identified by our research could inform interventions to achieve equitable distribution of county mortality rates.

Generational change in fasting glucose and insulin among children at ages 5-16y: Modelled on the EarlyBird study (2015) and UK growth standards (1990) (EarlyBird 69)

AIM

Pre-diabetes is a state of beta-cell stress caused by excess demand for insulin. Body mass is an important determinant of insulin demand, and BMI has risen substantially over recent time. We sought to model changes in the parameters of glucose control against rising BMI over the past 25years.

METHODS

Using random coefficient mixed models, we established the correlations between HbA1C, fasting glucose, fasting insulin, HOMA2-IR and BMI in contemporary (2015) children (N=307) at ages 5-16y from the EarlyBird study, and modelled their corresponding values 25years ago according to the distribution of BMI in the UK Growth Standards (1990).

RESULTS

There was little change in HbA1C or fasting glucose over the 25y period at any age or in either gender. On the other hand, the estimates for fasting insulin and HOMA2-IR were substantially higher in both genders in 2015 compared with 1990.

CONCLUSION

Insofar as it is determined by body mass, there has been a substantial rise in beta cell demand among children over the past 25years. The change could be detected by fasting insulin and HOMA2-IR, but not by fasting glucose or HbA1C.

Sensitivity to reward and punishment: Associations with fat and sugar intake among South African students

This study examined whether higher sensitivity to reward predicted higher fat and sugar intake among a sample of South African students at a university in the Western Cape and explored whether this relationship was mediated by food cue responsivity. It also examined whether sensitivity to punishment predicted higher fat and sugar intake among those who eat in response to anxiety. University students ( n = 320) completed a series of questionnaires that measured sensitivity to reward and punishment, diet, their tendency towards hedonic eating, and their tendency towards eating in response to anxiety. Results showed that higher sensitivity to reward predicted higher fat intake. This relationship was partially mediated by eating in response to food-rich environments (hedonic eating). Sensitivity to punishment failed to predict diet. The results of this study add to the growing body of evidence showing a relationship between sensitivity to reward and eating behaviours, and how this relationship might play out in a university environment.