Baseline serum β-carotene concentration and mortality among long-term asbestos-exposed insulators
Dana Hashim1, Denise Gaughan2, Paolo Boffetta3
1Icahn School of Medicine at Mount Sinai, New York, New York. Icahn School of Medicine at Mount Sinai, Institution of Translation Epidemiology, New York, New York. Icahn School of Medicine at Mount Sinai, Division of Occupational and Environmental Medicine, New York, New York. dana.hashim@mssm.edu.
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 nonsupplemented serum β-carotene to all-cause and cancer mortalities using 1981 to 1983 serum β-carotene concentration measurements from 2,646 U.S. white male insulators (mean age, 57.7 years). Multivariable-adjusted Cox proportional hazard models that included terms for age, duration of asbestos exposure, smoking, season, and region were fitted to estimate mortality HRs and 95% confidence intervals (CI) according to serum β-carotene concentrations.
Results:
Median follow-up was 12.8 years 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 with 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 (66-104 μg/dL), and 0.63 (95% CI, 0.51-0.77) for the highest serum β-carotene quartile (≥105 μg/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 nonsupplemented 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. Cancer Epidemiol Biomarkers Prev; 24(3); 555-60. ©2014 AACR.