Particulate matter air pollution components and risk for lung cancer

BACKGROUND

Particulate matter (PM) air pollution is a human lung carcinogen; however, the components responsible have not been identified. We assessed the associations between PM components and lung cancer incidence.

METHODS

We used data from 14 cohort studies in eight European countries. We geocoded baseline addresses and assessed air pollution with land-use regression models for eight elements (Cu, Fe, K, Ni, S, Si, V and Zn) in size fractions of PM2.5 and PM10. We used Cox regression models with adjustment for potential confounders for cohort-specific analyses and random effect models for meta-analysis.

RESULTS

The 245,782 cohort members contributed 3,229,220 person-years at risk. During follow-up (mean, 13.1 years), 1878 incident cases of lung cancer were diagnosed. In the meta-analyses, elevated hazard ratios (HRs) for lung cancer were associated with all elements except V; none was statistically significant. In analyses restricted to participants who did not change residence during follow-up, statistically significant associations were found for PM2.5 Cu (HR, 1.25; 95% CI, 1.01-1.53 per 5 ng/m(3)), PM10 Zn (1.28; 1.02-1.59 per 20 ng/m(3)), PM10 S (1.58; 1.03-2.44 per 200 ng/m(3)), PM10 Ni (1.59; 1.12-2.26 per 2 ng/m(3)) and PM10 K (1.17; 1.02-1.33 per 100 ng/m(3)). In two-pollutant models, associations between PM10 and PM2.5 and lung cancer were largely explained by PM2.5 S.

CONCLUSIONS

This study indicates that the association between PM in air pollution and lung cancer can be attributed to various PM components and sources. PM containing S and Ni might be particularly important.

Effect of enzyme induction on bioavailability of hetacillin in patients treated with anticonvulsants and chlorpromazine

The effect of liver enzyme induction on bioavailability of hetacillin was studied in patients chronically treated with anticonvulsants or chlorpromazine. 24 chronic psychiatric patients classified according to their medication in two groups (anticonvulsants, chlorpromazine) and one group of 11 healthy volunteers, received an i.m. administration of 500 mg hetacillin. Serum levels of ampicillin derived from hetacillin in blood samples taken 2, 4 and 6 hours after the injection were measured and the half-life of the antibiotic was determined for each group. Urinary D-glucaric acid was considered the induction index. Correlation coefficients between the induction index and pharmacokinetic parameters of hetacillin were also determined. Anticonvulsants and chlorpromazine induced the liver microsomal enzymes as demonstrated by the increased D-glucaric acid excretion (P less than 0.001 - P less than 0.05). No statistically significant differences were found in serum levels and half-life of the antibiotic. Correlation coefficients suggest that enzyme induction and hetacillin bioavailability are not significantly related.