Flexible Two-Phase studies for rare exposures: Feasibility, planning and efficiency issues of a new variant.

The two-phase design consists of an initial (Phase One) study with known disease status and inexpensive covariate information. Within this initial study one selects a subsample on which to collect detailed covariate data. Two-phase studies have been shown to be efficient compared to standard case-control designs.

Update of a meta-analysis on lung cancer and welding.

Objectives: This study is an update, over the period 1954-2004, of a previous meta-analysis completed in 1994. It was aimed at assessing lung cancer risk among welders, while addressing heterogeneity, publication bias, and confounding issues.

Methods: Combined relative risks (CRR) and their variances were calculated using fixed and random effects models.

A meta-analysis of epidemiologic studies of lung cancer in welders.

Objective: A meta-analysis of epidemiologic studies was carried out on lung cancer risk among shipyard, mild steel, and stainless steel welders, and the role of asbestos exposure and smoking was considered.

Methods: The meta-analysis consisted of calculating combined relative risks (RR) and their variances through a logarithm transformation of published RR values and a weighing using the inverted variance of each RR.

Results: The literature provided 18 case-referent and 31 cohort studies.

Mortality study among workers producing ferroalloys and stainless steel in France.

A mortality study was carried out among the workers of a plant that had produced ferrochromium and stainless steel, and was still producing stainless steel, in order to determine whether exposure to chromium compounds, to nickel compounds, and to polycyclic aromatic hydrocarbons (PAH) could result in a risk of lung cancer for the exposed workers. The cohort comprised 2269 men whose vital status were recorded between 1 January 1952 and 31 December 1982. The smoking habits of 67% of the cohort members were known from medical records.