Background:Traffic noise affects a large number of people, particularly in urbanized areas. Noise causes stress and annoyance, but less is known about the relationship between noise and depression.Objective:We investigated the association of residential road traffic noise with depressive symptoms using 5-year follow-up data from a German population-based study.Methods:We analyzed data from 3,300 participants in the Heinz Nixdorf Recall study who were between 45 and 75 years old and were without depressive symptoms at baseline (2000–2003). Depressive symptoms were defined based on the Center for Epidemiologic Studies Depression scale (CES-D) 15-item questionnaire (total score ≥ 17) and antidepressant medication intake. Road traffic noise was modeled according to European Parliament/Council Directive 2002/49/EC. High noise exposure was defined as annual mean 24-hr noise levels > 55 A-weighted decibels [dB(A)]. Poisson regression with robust variance was used to estimate relative risks (RRs) a) adjusting for the potential confounders age, sex, socioeconomic status (SES), neighborhood-level SES, and traffic proximity; b) additionally adjusting for body mass index and smoking; and c) additionally adjusting for the potential confounders/intermediates comorbidities and insomnia.Results:Overall, 35.7% of the participants were exposed to high residential road traffic noise levels. At follow-up (mean = 5.1 years after baseline), 302 participants were classified as having high depressive symptoms, corresponding to an adjusted RR of 1.29 (95% CI: 1.03, 1.62; Model 1) for exposure to > 55 versus ≤ 55 dB(A). Adjustment for potential confounders/intermediates did not substantially alter the results. Associations were stronger among those who reported insomnia at baseline (RR = 1.62; 95% CI: 1.10, 2.59 vs. RR = 1.21; 95% CI: 0.94, 1.57) and appeared to be limited to those with ≤ 13 years of education (RR = 1.43; 95% CI: 1.10, 1.85 vs. 0.92; 95% CI: 0.56, 1.53 for > 13 years).Conclusion:Our results suggest that exposure to residential road traffic noise increases the risk of depressive symptoms.Citation:Orban E, McDonald K, Sutcliffe R, Hoffmann B, Fuks KB, Dragano N, Viehmann A, Erbel R, Jöckel KH, Pundt N, Moebus S. 2016. Residential road traffic noise and high depressive symptoms after five years of follow-up: results from the Heinz Nixdorf Recall Study. Environ Health Perspect 124:578–585; http://dx.doi.org/10.1289/ehp.1409400

The literature on the role of body iron status in the development of type 2 diabetes (T2D) in humans is inconsistent. We aimed to assess the association between iron indices and T2D by a meta-analysis of previously published studies. A systematic literature search was conducted in PubMed and EMBASE. Observational studies on the association of ferritin (when controlled for age and sex), transferrin saturation, soluble transferrin receptor and transferrin with T2D were included. Pooled association estimates were calculated using a random effects model. Forty-six eligible studies were identified. The pooled multivariable adjusted relative risks of T2D in the highest versus lowest quartile of ferritin levels were significantly elevated in both cross-sectional as well as prospective studies and after restriction to inflammation-adjusted studies [overall: 1.67 (95% CI 1.41-1.99)]. The mean difference indicated 43.54 ng/mL (95% CI 28.14-58.94) higher ferritin levels in type 2 diabetic individuals. The relative risk for a transferrin saturation ≥ 50% was 1.59 (95% CI 1.28-1.97), the mean difference was -1.92% [95% CI -2.99-(-0.85)]. Study-specific results of soluble transferrin receptor and transferrin levels were extremely heterogeneous. Ferritin and clinically elevated transferrin saturation were strongly associated with an increased risk of T2D, overall and in prospective studies. Ferritin was also significantly associated after multivariable adjustment including inflammation. Thus, the current evidence hints at a causal effect; however, publication bias and unmeasured confounding cannot be excluded.