Baseline serum Β-carotene concentration and mortality among long-term asbestos-exposed insulators
Menée auprès de 2 646 participants masculins (âge moyen : 57,7 ans), cette étude analyse l'association entre la concentration sérique de béta-carotène et la mortalité par cancer chez des salariés exposés à l'amiante
Background: Although interventional trials demonstrated that moderate-dose β -carotene supplementation increases lung cancer mortality in smokers and asbestos-exposed workers, differences in serum concentrations in absence of supplementation have not been studied in asbestos-exposed workers. Methods: A mortality analysis was performed to assess the relationship of non-supplemented serum β-carotene to all-cause and cancer mortalities using 1981-1983 serum β-carotene concentration measurements from 2,646 US white male insulators (mean age 57.7 y). Multivariable-adjusted Cox proportional hazard models that included terms for age, duration of asbestos exposure, smoking, season, and region were fitted to estimate mortality hazard ratios (HR) and 95% confidence intervals (CI) according to serum β-carotene concentrations. Results: Median follow-up was 12.8 y and 984 (33.8%) subjects died during the follow-up period, including 415 deaths from overall cancer and 219 deaths from lung cancer. The overall mortality HR for a serum β-carotene increase of 10 µg/dL was 0.97 (95% CI: 0.96, 0.99). Compared to the lowest quartile, HRs were 0.90 (95% CI: 0.76, 1.07) for the second (38-65 µg/dl), 0.80 (95% CI: 0.67, 0.96) for the third (66-104µg/dl), and 0 0.63 (95% CI: 0.51, 0.77) for the highest serum β-carotene quartile (≥105µg/dl). There was no association between serum β-carotene and overall cancer mortality (HR: 1.00; 95% CI: 0.97, 1.02) or lung cancer mortality (HR: 0.99; 95% CI: 0.96, 1.02). Conclusions: Higher non-supplemented serum β-carotene concentrations were negatively associated with all-cause mortality among asbestos-exposed individuals. Impact: Serum β-carotene can be a marker of one or more determinants of reduced mortality in asbestos-exposed workers.