BACKGROUND: Traffic noise can act as a stressor and disturb sleep, and has been associated with cardiovascular disease. Recent studies suggest a possible association to metabolic outcomes and adiposity through biological mechanisms related to physiological stress and sleep disturbance.

OBJECTIVES: We aimed to investigate the association between long-term residential traffic noise and changes in adiposity.

MATERIALS AND METHODS: The study was based on 39,720 middle-aged Danish men and women from a cohort, with information on weight and waist circumference at two points in time. Residential exposure to traffic noise was calculated for all participants' present and historical addresses using the Nordic prediction method. The associations between traffic noise and changes in adiposity measures after a mean follow-up of 5.3 years were analyzed by linear and logistic regression with adjustments for age, sex, socioeconomic position and lifestyle factors in three models with increasing adjustment.

RESULTS: In linear models adjusted for sex, age, socioeconomic position and competing noise sources we found road traffic noise to be significantly associated with small gains in both weight and waist circumference. For example, time-weighted mean exposure 5-years preceding follow-up was associated with a yearly weight gain of 15.4g (95% confidence interval (CI): 2.14; 28.7) and a yearly increase in waist circumference of 0.22mm (95% CI: 0.018; 0.43) per 10dB. Similarly, in Poisson regression models we found an 10% increased risk for gaining more than 5kg body weight during follow-up (95% CI: 1.04; 1.15) per 10dB higher 5 years exposure preceding follow-up. Exposure to railway noise above 55dB was associated with weight gain (39.9g/year (95% CI: 10.2; 69.6)), but not with a significant change in waist circumference. We found baseline BMI (p<0.001) and waist circumference (p=0.001) to be significant effect modifiers for the association between road traffic noise and waist circumference, with gain in waist circumference only among the obese (BMI≥30) participants (1.20mm/year (95% CI: 0.68; 1.72)) and participants with a large waist circumference (0.83mm/year (95% CI: 0.42; 1.23)).

CONCLUSION: The findings supports previous studies suggesting that traffic noise may be associated with development of adiposity. However, the potential effects are small and suggest an effect mainly among obese participants.