Long-term Air Pollution and Overall and Regional Body Composition in Older Adults With Overweight or Obesity and Metabolic Syndrome

OBJECTIVE: To examine the relationship between long-term air pollution exposure, including black carbon (BC), fine particulate matter (PM2.5), and nitrogen dioxide (NO2), and total fat mass, visceral fat mass, and lean mass in older adults with overweight or obesity and metabolic syndrome. RESEARCH DESIGN AND METHODS: We included 1,454 older adults (aged 54-75 years; 48% female) from the PREDIMED-Plus trial in Spain who underwent baseline DXA scans at recruitment (2013-2016) and at 1- and 3-year follow-up. Annual air pollution exposure was assigned at participants' baseline residential address at 100 m resolution. We used linear mixed-effect regression models with interaction terms for exposure and time to examine longitudinal associations with body composition, also stratifying by sex, age, and physical activity. RESULTS: At baseline, a 1 × 10-5/m increase in BC was associated with 1.01% (95% CI 0.31-1.71) higher body fat percentage, -0.97% (95% CI -1.64 to -0.30) lower lean mass percentage, and -0.74 kg (95% CI -1.37 to -0.12) lower lean mass. PM2.5 and NO2 showed similar relationships with body fat and lean mass percentage at baseline. These associations persisted in years 1 and 3 for BC and PM2.5. In age-stratified analyses, associations with visceral fat mass were observed only in participants younger than 65 years. Associations did not meaningfully differ by sex or physical activity. CONCLUSIONS: Long-term air pollution exposure was adversely associated with body composition over 3 years. Results indicate air pollution is associated with fat accumulation and lean mass loss in metabolically vulnerable older adults.