Gene-Environment Interaction of FOXO and Residential Greenness on Mortality Among Older Adults

Association between residential greenness and all-cause mortality and the joint mediation effect of air pollutants among old people with disability: A prospective cohort study

BACKGROUND

Residential greenness offers health benefits to old people, but evidence of its association with the health of old people with disability is scarce. Moreover, due to the limited mobility of this vulnerable population, air pollutants may play an indispensable mediating role in that association, which however remains understudied.

OBJECTIVES

This study aimed to investigate the association between residential greenness and all-cause mortality risk and the joint mediation effect of air pollutants among old people with disability.

METHODS

A total of 34,075 old people with disability were included in the Chengdu Long-term Care Insurance cohort. Participants' residential greenness exposure was measured by an enhanced vegetation index within the 500 m buffer zone (EVI_500m). Causal mediation analysis was conducted to assess the total effect (TE) of residential greenness and the natural indirect effect (NIE) through PM_2.5, CO, NO₂, SO₂, and O₃ on all-cause mortality.

RESULTS

The TE of EVI_500m on the all-cause mortality risk in overall participants showed negative, which, decreased from the 2^nd quartile (HR = 0.93, 95 % CI: 0. 91, 0.95) to the 4^th quartile (HR = 0.81, 95 % CI: 0.76, 0.85); the NIE through the five air pollutants also decreased from the 2^nd quartile (HR = 0.96, 95 % CI: 0.95, 0.98) to the 4^th quartile (HR = 0.90, 95 % CI: 0.88, 0.93), with the proportion mediated decreased from 48 % to 44 %. The stronger TE or NIE were observed in participants aged <80 years old, men, with mild-moderate disability, and having outdoor experience every week.

CONCLUSION

Exposure to residential greenness was associated with a decreased risk of mortality, partially through the pathways of air pollutants, which varied by age, sex, degree of disability, and frequency of weekly outdoors. Our findings would provide evidence to develop aging-friendly cities.

Energy Homeostasis Gene Nucleotide Variants and Survival of Hemodialysis Patients-A Genetic Cohort Study

Background: Patients undergoing hemodialysis (HD) therapy have an increased risk of death compared to the general population. We investigated whether selected single nucleotide variants (SNVs) involved in glucose and lipid metabolism are associated with mortality risk in HD patients. Methods: The study included 805 HD patients tested for 11 SNVs in FOXO3, IGFBP3, FABP1, PCSK9, ANGPTL6, and DOCK6 using HRM analysis and TaqMan assays. FOXO3, IGFBP3, L-FABP, PCSK9, ANGPTL6, and ANGPTL8 plasma concentrations were measured by ELISA in 86 individuals. The Kaplan–Meier method and Cox proportional hazards models were used for survival analyses. Results: We found out that the carriers of a C allele in ANGPTL6 rs8112063 had an increased risk of all-cause, cardiovascular, and cardiac mortality. In addition, the C allele of DOCK6 rs737337 was associated with all-cause and cardiac mortality. The G allele of DOCK6 rs17699089 was correlated with the mortality risk of patients initiating HD therapy. The T allele of FOXO3 rs4946936 was negatively associated with cardiac and cardiovascular mortality in HD patients. We observed no association between the tested proteins’ circulating levels and the survival of HD patients. Conclusions: The ANGPTL6 rs8112063, FOXO3 rs4946936, DOCK6 rs737337, and rs17699089 nucleotide variants are predictors of survival in patients undergoing HD.

Comparing Effects of FOXO3A and Residing in Urban Areas on Longevity: A Gene-Environment Interaction Study

Forkhead box O3 (FOXO3A) is a candidate longevity gene. Urban residents are also positively associated with longer life expectancy. We conducted a gene-environment interaction to assess the synergistic effect of FOXO3A and urban/rural environments on mortality. We included 3085 older adults from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We used single nucleotide polymorphisms (SNPs) rs2253310, rs2802292, and rs4946936 to identify the FOXO3A gene and classified residential locations as "urban" and "rural." Given the open cohort design, we used the Cox-proportional hazard regression models to assess the mortality risk. We found the minor allele homozygotes of FOXO3A to have a protective effect on mortality [HR (95% CI) for rs4946936 TT vs. CC: 0.807 (0.653, 0.996); rs2802292 GG vs TT: 0.812 (0.67, 0.985); rs2253310 CC vs. GG: 0.808 (0.667, 0.978)]. Participants living in urban areas had a lower risk of mortality [HR of the urban vs. the rural: 0.854 (0.759, 0.962)]. The interaction between FOXO3A and urban and rural regions was statistically significant (pinteraction<0.01). Higher air pollution (fine particulate matter: PM2.5) and lower residential greenness (Normalized Difference Vegetation Index: NDVI) both contributed to higher mortality. After adjusting for NDVI and PM2.5, the protective effect size of FOXO3A SNPs was slightly attenuated while the protective effect size of living in an urban environment increased. The effect size of the beneficial effect of FOXO3 on mortality is roughly equivalent to that of living in urban areas. Our research findings indicate the effect of places of residence and genetic predisposition of longevity are intertwined.

Environmental Influences on Sleep in the California Teachers Study Cohort

Only two-thirds of Americans meet the recommended 7 hours of sleep nightly. Insufficient sleep and circadian disruption have been associated with adverse health outcomes, including diabetes and cardiovascular disease. Several environmental disruptors of sleep have been reported, such as artificial light at night (ALAN) and noise. These studies tended to evaluate exposures individually. We evaluated several spatially derived environmental exposures (ALAN, noise, green space, and air pollution) and self-reported sleep outcomes obtained in 2012-2015 in a large cohort of 51,562 women in the California Teachers Study. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for sleep duration and latency. After adjusting for age, race/ethnicity, chronotype, use of sleep medication, and self-reported trouble sleeping, ALAN (per 5 millicandela (mcd)/m2 luminance, OR = 1.13, 95% CI: 1.07, 1.20) and air pollution (per 5 μg/m3 PM2.5, OR = 1.06, 95% CI: 1.04, 1.09) were associated with shorter sleep duration (<7 hours), and noise was associated with longer latency (>15 minutes) (per 10 decibels, OR = 1.05, 95% CI: 1.01, 1.10). Green space was associated with increased duration (per 0.1 units, OR = 0.41, 95% CI: 0.28, 0.60) and decreased latency (per 0.1 units, OR = 0.55, 95% CI: 0.39, 0.78). Further research is necessary to understand how these and other exposures (e.g., diet) perturb an individuals' inherited sleep patterns and contribute to downstream health outcomes.