Baseline Serum β-carotene Concentration and Mortality among Long-Term Asbestos-Exposed Insulators

Abstract

Background: Although interventional trials demonstrated that moderate-dose b-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 b-carotene to all-cause and cancer mortalities using 1981 to 1983 serum b-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 b-carotene concentrations.Results: Median follow-up was 12.8 years and 984 (33.8%) subjects died during the follow-up period, including 415

Re: Terracini et al. Comments on the causation of malignant mesothelioma: Rebutting the false concept that recent exposures to asbestos do not contribute to causation of mesothelioma. Am J Ind Med 2016;59:506‐507

“…In general, the conclusions we reached in our 2012 review [La Vecchia and Boffetta, ] are based on the scientific evidence, independent from any litigation. They are fully consistent with the rest of my work on asbestos and disease, which has always aimed at contributing to the advancement of the understanding of the health effects of this agent [e.g., Carel et al, ; Hashim et al, ].…”

Body Weight, Cholesterol Changes and Sub-Chronic Toxicity of Mice Treated with An Emulsion Product Rich in b-Carotene

“…Additional treatment of β-carotene and emulsion successfully prevented increase in creatinine levels in mice given egg yolks. These results are in harmony with the phenomenon of antioxidant protective effects, such as β-carotene and vitamin C, against oxidative stress for patients with human kidney function deficiency 30 and mice 31,32 .…”

Dietary Antioxidants, Circulating Antioxidant Concentrations, Total Antioxidant Capacity, and Risk of All-Cause Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Observational Studies

“…Eight studies used HPLC for measurement of circulating β-carotene, but 1 study (the asbestos-exposed insulators cohort study) did not report the method of assessment (47). The linear trend estimation indicated that a 0.10-µmol/L increment in circulating β-carotene concentration was associated with a 4% lower risk (RR: 0.96; 95% CI: 0.94, 0.98; I 2 = 61.4%, P heterogeneity = 0.02; n = 6 studies) (Supplemental Figure 4, Table 1).…”

“…The linear trend estimation indicated that a 0.10-µmol/L increment in circulating β-carotene concentration was associated with a 4% lower risk (RR: 0.96; 95% CI: 0.94, 0.98; I 2 = 61.4%, P heterogeneity = 0.02; n = 6 studies) (Supplemental Figure 4, Table 1). In the sensitivity analysis removing each study in turn, the asbestos-exposed insulators cohort study (47) accounted for all of the observed heterogeneity (RR: 0.95; 95% CI: 0.94, 0.97; I 2 = 0%), but none of the excluded studies changed the summary result materially (RR range: 0.95-0.98). There was a linear association between circulating β-carotene concentration and risk of all-cause mortality (P for nonlinearity = 0.15, n = 5 studies) ( Figure 2B).…”