Longitudinal Examination of Hair Cortisol Concentrations and Weight Changes in Preschool-Aged Children of Latino Farmworkers.

Background: Hair cortisol concentrations may serve as a measure of biologically embedded stress. While the cross-sectional association between hair cortisol and obesity in children has been examined, the data examining this relationship over time are limited. Methods: We examined hair cortisol and anthropometrics in 40 children with obesity from Latino families enrolled in a Head Start program serving farmworkers. All participants were enrolled in a clinical trial using parent mentors to encourage healthy lifestyles. We analyzed the proximal 3 cm of hair at the beginning and the end of the trial, a period of about 8 months. Linear mixed models were used to examine if changes in hair cortisol were associated with changes in adiposity. Results: Children had a median BMI percentile of 98% and parents with lower education with 25 of 40 having less than high school diploma and high food insecurity (17 of 40, 43%). Among the 40 children with valid data for both time points, the median hair cortisol concentration at baseline was 4.09 pg/mg (interquartile range [IQR] 2.65-8.68) and 6.05 pg/mg (IQR 3.95-9.33) at the end point. Increases in cortisol from baseline to follow-up had a small but significant association with decreased obesity over time. Hair cortisol did not moderate an association between food security and weight. Conclusion: In children with chronic stressors and obesity, we found that increases in cortisol over time were associated with decreases in adiposity. Further studies following hair cortisol concentrations over time are needed to understand how this biomarker relates to weight status and stressors. Clinicaltrials.gov ID: NCT03330743.

Growing Healthy Together: A Randomized Clinical Trial Using Parent Mentors for Early Childhood Obesity in Low-Income, Latino Families.

Background: Parent mentors are a potential community-based mechanism for delivering behavioral interventions. For communities at a higher risk of obesity and challenges with access to care, such as migrant and seasonal farm workers, this may be an effective intervention for obesity. This study examined the effect of parent mentors on weight outcomes. Methods: This randomized clinical trial assigned parents of 2- to 5 year-old children enrolled in Head Start 1:1:1 to control, a parent mentor teaching We Can!, or a parent mentor teaching an intervention derived from positive deviance methods. The parent mentor arms were designed to have weekly interactions and monthly community meetings over 6 months. The primary outcome was change in adiposity, as measured by body mass indices. Results: We randomized 188 parents, and 155 completed the 6-month visit. Most parents, 107 (58%), had less than a high school education, and 170 (90%) reported Latino ethnicity. In the intention-to-treat analysis, no difference between the groups was observed for change in percent distance from the median or BMI z-score. The median number of interactions was 14 (IQR 10-20) over 6 months for those who did engage, though 24 of 118 (20%) had no interaction. Those with no interactions in We Can! had a mean increase in change from median of 6.7 [standard deviation (SD) = 8.2]; those with higher participation experienced a 0.4 (SD = 9.2) change, p = 0.04. Conclusions: Parent mentors were not effective in changing the adiposity indices in this study overall, with some evidence of efficacy after accounting for participation. Clinicaltrials.gov registration number: NCT03330743.

A genetic screen for temperature-sensitive morphogenesis-defective Caenorhabditis elegans mutants.

Morphogenesis involves coordinated cell migrations and cell shape changes that generate tissues and organs, and organize the body plan. Cell adhesion and the cytoskeleton are important for executing morphogenesis, but their regulation remains poorly understood. As genes required for embryonic morphogenesis may have earlier roles in development, temperature-sensitive embryonic-lethal mutations are useful tools for investigating this process. From a collection of ∼200 such Caenorhabditis elegans mutants, we have identified 17 that have highly penetrant embryonic morphogenesis defects after upshifts from the permissive to the restrictive temperature, just prior to the cell shape changes that mediate elongation of the ovoid embryo into a vermiform larva. Using whole genome sequencing, we identified the causal mutations in seven affected genes. These include three genes that have roles in producing the extracellular matrix, which is known to affect the morphogenesis of epithelial tissues in multicellular organisms: the rib-1 and rib-2 genes encode glycosyltransferases, and the emb-9 gene encodes a collagen subunit. We also used live imaging to characterize epidermal cell shape dynamics in one mutant, or1219ts, and observed cell elongation defects during dorsal intercalation and ventral enclosure that may be responsible for the body elongation defects. These results indicate that our screen has identified factors that influence morphogenesis and provides a platform for advancing our understanding of this fundamental biological process.