DRD4 genotype predicts longevity in mouse and human.

Longevity is influenced by genetic and environmental factors. The brain's dopamine system may be particularly relevant, since it modulates traits (e.g., sensitivity to reward, incentive motivation, sustained effort) that impact behavioral responses to the environment. In particular, the dopamine D4 receptor (DRD4) has been shown to moderate the impact of environments on behavior and health. We tested the hypothesis that the DRD4 gene influences longevity and that its impact is mediated through environmental effects. Surviving participants of a 30-year-old population-based health survey (N = 310; age range, 90-109 years; the 90+ Study) were genotyped/resequenced at the DRD4 gene and compared with a European ancestry-matched younger population (N = 2902; age range, 7-45 years). We found that the oldest-old population had a 66% increase in individuals carrying the DRD4 7R allele relative to the younger sample (p = 3.5 × 10(-9)), and that this genotype was strongly correlated with increased levels of physical activity. Consistent with these results, DRD4 knock-out mice, when compared with wild-type and heterozygous mice, displayed a 7-9.7% decrease in lifespan, reduced spontaneous locomotor activity, and no lifespan increase when reared in an enriched environment. These results support the hypothesis that DRD4 gene variants contribute to longevity in humans and in mice, and suggest that this effect is mediated by shaping behavioral responses to the environment.

Chainsaw operators' exposure to occupational risk factors and incidence of professional diseases specific to the forestry field.

Purpose. This article focuses on detailed studies regarding the analysis of occupational risk factors on health and occupational disease, namely, the influence of noise, hand-arm vibration, wet bulb globe temperature (WBGT) index and exposure to particulates. Methods. This study measured the equivalent acoustic level (LAeq), daily vibration exposure (A(8)), WBGT index and particulate concentration in the respirable area of the worker. The inferential analysis consisted of the application of specific statistical methods: a probability plot with 95% confidence interval, the Anderson-Darling statistic and 87th percentile estimation. A sample of 107 chainsaw operators was medically evaluated, out of which 30 workers were suspected of having professional pathologies and were hospitalized in the university clinic. Results. The measurements highlight: exceeding the legal limit for noise exposure; 13% of cases exceeding the limit of 2.5 m/s2 for hand-arm vibration; dust exposure generally within legal limits; WBGT shows the thermal stress of the workers. Following the medical evaluation, osteomusculoskeletal disorders (25.23%), Raynaud's syndrome (0.93%) and bilateral hearing loss (3.74%) were identified. Conclusions. Analysis of the levels of exposure to the risk factors, the typology and the incidence of occupational diseases requires the need to adopt new preventive measures.