Long-Term Exposure to Ambient PM2.5, Sunlight, and Obesity: A Nationwide Study in China

BackgroundAccumulated researches revealed that both fine particulate matter (PM2.5) and sunlight exposure may be a risk factor for obesity, while researches regarding the potential effect modification by sunlight exposure on the relationship between PM2.5 and obesity are limited. We aim to investigate whether the effect of PM2.5 on obesity is affected by sunlight exposure among the general population in China.MethodsA sample of 47,204 adults in China was included. Obesity and abdominal obesity were assessed based on body mass index, waist circumference and waist-to-hip ratio, respectively. The five-year exposure to PM2.5 and sunlight were accessed using the multi-source satellite products and a geochemical transport model. The relationship between PM2.5, sunshine duration, and the obesity or abdominal obesity risk was evaluated using the general additive model.ResultsThe proportion of obesity and abdominal obesity was 12.6% and 26.8%, respectively. Levels of long-term PM2.5 ranged from 13.2 to 72.1 μg/m3 with the mean of 46.6 μg/m3. Each 10 μg/m3 rise in PM2.5 was related to a higher obesity risk [OR 1.12 (95% CI 1.09-1.14)] and abdominal obesity [OR 1.10 (95% CI 1.07-1.13)]. The association between PM2.5 and obesity varied according to sunshine duration, with the highest ORs of 1.56 (95% CI 1.28-1.91) for obesity and 1.66 (95% CI 1.34-2.07) for abdominal obesity in the bottom quartile of sunlight exposure (3.21-5.34 hours/day).ConclusionLong-term PM2.5 effect on obesity risk among the general Chinese population are influenced by sunlight exposure. More attention might be paid to reduce the adverse impacts of exposure to air pollution under short sunshine duration conditions.

Direct and Indirect Relationships Between Impaired Sleep, Obesity Risk Factors and Overweight and Obesity

PurposeThe relationship between impaired sleep and overweight/obesity may be explained by sleep-disrupting behaviour that are practised by overweight people (e.g. night-eating, insufficient physical activity [PA], electronic device use) and stress/affective distress. Thus, we evaluated whether sleep parameters predicted overweight/obesity after taking into account the behaviour and affective state.MethodsOnline questionnaires asked about sleep quality, night-eating, PA, electronic device use and stress/affective distress at T1 (baseline) and T2 (3-months later). Height, weight and waist and hip circumference were measured. PA and sleep were assessed over 24-hours on two occasions using actigraphy in 161 participants at T1 and T2.ResultsAt T1, high body mass index (BMI)/waist-to-hip ratio (WHR) and obesity category were together related to more sleep disturbances (subjective) and longer awake time (objective), after controlling covariates (e.g. watching TV) and demographics (e.g. older age, male gender). At T2, high WHR was predicted by older age and male gender after controlling T1 WHR, demographics and covariates. Mediational analyses showed that sleep disturbances mediated nocturnal indigestion (NI) to BMI, poor subjective sleep quality mediated NI to WHR and high daytime dysfunction mediated NI to obesity category relationships.ConclusionMore time spent awake during the night (experienced as more sleep disturbances) was related to overweight/obesity indices even after taking into account other obesity risk factors (e.g. night-eating, insufficient PA, affect) and demographics. Mediational results suggest that NI parsimoniously explained the impaired sleep - overweight/obesity relationship.Level of Evidence: Level III, evidence obtained from well-designed cohort.

Association of Regular Leisure-Time Physical Activity with Self-Reported Body Mass Index and Obesity Risk among Middle-Aged and Older Adults in Taiwan

Through this study, we aimed to determine the association of regular leisure-time physical activity (LTPA) with self-reported body mass index (BMI) and obesity risk among middle-aged and older adults in Taiwan. We conducted a cross-sectional study and reviewed the data derived from the Taiwan National Physical Activity Survey (TNPAS). Responses from 12,687 participants aged 45–108 years from the database were collected in this study. All the participants completed a standardized structured questionnaire that solicitated information regarding their demographic characteristics (age, gender, education, occupation, and self-reported health status), physical activity behaviors (regular/nonregular LTPA), and self-reported anthropometrics (height, weight, and BMI). Multiple linear and logistic regressions were used to examine the association between regular LTPA and BMI, and between regular LTPA and obesity status, respectively. Regular LTPA was associated with male gender, normal weight, excellent or good self-reported health status, and a lower rate of being underweight compared with nonregular LTPA. Regular LTPA was significant negatively associated with being underweight (OR = 0.71, p < 0.05), whereas it had no significant relationship with BMI and obesity (p > 0.05). Regular LTPA was associated with a reduced risk of being underweight among middle-aged and elderly adults in Taiwan. Further research on the relevant mechanism underlying this phenomenon is warranted.

How beliefs about weight malleability and risk perceptions for obesity influence parents’ information seeking and feeding

This study surveyed 185 parents to determine whether their perceived risk of their child developing obesity and their implicit theories about the malleability of weight independently and/or interactively predict their child-feeding and pursuit of child-related obesity risk information. Higher risk perceptions were associated with healthier feeding intentions and more information seeking. More incremental (malleable) beliefs predicted healthier feeding intentions and greater pursuit of environmental, but not genetic, information. Contrary to hypotheses, the influence of implicit theories and risk perceptions were primarily independent; however, more incremental beliefs predicted less “junk food” feeding among only parents with lower perceived risk.

Food Insecurity, Food Environments, and Disparities in Diet Quality and Obesity

Food insecurity is a public health concern that is associated with poor diet and obesity. Poor food environments with low access to healthy, affordable food may amplify the negative impact of food insecurity on diet and obesity. This study aims to investigate whether food insecurity and food environments are jointly associated with an increased risk of poor diet quality and obesity. We used data from a nationally representative sample of 6,395 older adults in the Health and Retirement Study Health Care and Nutrition Survey and the National Neighborhood Data Archive. Weighted regression models were estimated to examine the relationship between food insecurity and food environments with diet quality and obesity. Both food insecurity and poor food environment were associated with lower healthy eating index scores, indicating poorer quality diet. Food insecure older adults were more likely to be obese than food secure older adults and poor food environments exacerbate the negative impact of food insecurity on obesity risk. However, there was no statistical difference in obesity risk by food environment among food secure respondents. Findings from this study highlight the negative impact of limited access to healthy food due to financial difficulties and/or poor food environments on diet quality and obesity risk. Providing financial or nutritional supports along with efforts to promote healthy food environment may reduce disparities in diet quality and obesity. Special support should be provided to food insecure older adults with poor food environment, those at the greatest risk of poor diet quality and obesity.