Kenji Obayashi1, Keigo Saeki1, Norio Kurumatani1. 1. Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara 634-8521, Japan.
Abstract
CONTEXT: Previous epidemiological studies have suggested an association between nighttime light levels and the prevalence of obesity, although evidence is limited to cross-sectional studies. OBJECTIVE: To evaluate the longitudinal association between ambient light exposure and the subsequent changes in obesity parameters. DESIGN AND PARTICIPANTS: Data from 1110 elderly participants at baseline (mean age, 71.9 years) and data from 766 at follow-up (median, 21 months) were included in this prospective population-based study. MEASURES: Time-dependent ambient light exposure based on objective measurements and changes in the waist-to-height ratio (WHtR) and body mass index (BMI) were measured. RESULTS: Multivariable mixed-effect linear regression models showed a significant association between light exposure and the %WHtR gain; this was independent of potential confounders (eg, caloric intake, physical activity, and sleep/wake parameters). Nighttime or evening exposure to higher light intensity was significantly associated with subsequent %WHtR gain. Morning exposure to a longer time ≥500 lux or nighttime exposure to a longer time <3 lux was significantly associated with subsequent %WHtR loss. These association trends were nearly consistent when the BMI was used as an obesity parameter. Increased nighttime light exposure (mean ≥3 vs <3 lux) was estimated to correspond to a 10.2% WHtR gain and a 10.0% increase in BMI over 10 years. CONCLUSIONS: Ambient light exposure, such as increased nighttime or evening light exposure and decreased morning light exposure, was independently associated with subsequent increases in obesity parameters. Further interventional studies are warranted to establish an optimal controlled lighting environment as a preventive option against obesity.
CONTEXT: Previous epidemiological studies have suggested an association between nighttime light levels and the prevalence of obesity, although evidence is limited to cross-sectional studies. OBJECTIVE: To evaluate the longitudinal association between ambient light exposure and the subsequent changes in obesity parameters. DESIGN AND PARTICIPANTS: Data from 1110 elderly participants at baseline (mean age, 71.9 years) and data from 766 at follow-up (median, 21 months) were included in this prospective population-based study. MEASURES: Time-dependent ambient light exposure based on objective measurements and changes in the waist-to-height ratio (WHtR) and body mass index (BMI) were measured. RESULTS: Multivariable mixed-effect linear regression models showed a significant association between light exposure and the %WHtR gain; this was independent of potential confounders (eg, caloric intake, physical activity, and sleep/wake parameters). Nighttime or evening exposure to higher light intensity was significantly associated with subsequent %WHtR gain. Morning exposure to a longer time ≥500 lux or nighttime exposure to a longer time <3 lux was significantly associated with subsequent %WHtR loss. These association trends were nearly consistent when the BMI was used as an obesity parameter. Increased nighttime light exposure (mean ≥3 vs <3 lux) was estimated to correspond to a 10.2% WHtR gain and a 10.0% increase in BMI over 10 years. CONCLUSIONS: Ambient light exposure, such as increased nighttime or evening light exposure and decreased morning light exposure, was independently associated with subsequent increases in obesity parameters. Further interventional studies are warranted to establish an optimal controlled lighting environment as a preventive option against obesity.
Authors: Julia E Stone; Tracey L Sletten; Michelle Magee; Saranea Ganesan; Megan D Mulhall; Allison Collins; Mark Howard; Steven W Lockley; Shantha M W Rajaratnam Journal: J Physiol Date: 2018-04-06 Impact factor: 5.182
Authors: Dong Zhang; Rena R Jones; Tiffany M Powell-Wiley; Peng Jia; Peter James; Qian Xiao Journal: Environ Health Date: 2020-07-01 Impact factor: 5.984