An adequate threshold for body mass index to detect underweight condition in elderly persons: the Italian Longitudinal Study on Aging (ILSA).

Background: The present study aims at defining a body mass index (BMI) threshold for risk of being underweight in elderly persons on the basis of the BMI distribution in a large Italian population-based sample and on its ability to predict short-term mortality.

Methods: At baseline (1992), BMI was obtained for 3110 (1663 males and 1447 females) persons aged 65-84 participating in the Italian Longitudinal Study on Aging (ILSA). BMI and risk factors (age, sex, education, smoking status, disability, and disease status) have been considered for their potential association with 4-year all-cause mortality.

Elevated lung cancer risk shortly after smoking cessation: is it due to a reduction of endotoxin exposure?

Several reports indicate that the risk of lung cancer increases slightly for a short period of time after cessation of smoking while the risk of adverse cardiovascular events drops immediately. Recent studies on subjects occupationally exposed to organic dust-containing endotoxin have revealed lower than expected rates of lung cancer. There is experimental evidence that stimulation of the immune system by endotoxin has a protective effect against cancer.

Lung cancer risk: effect of dairy farming and the consequence of removing that occupational exposure.

The aim of this study was to confirm the exposure-dependent reduction in lung cancer risk reported for dairy farmers exposed to endotoxin and to evaluate the consequence of leaving dairy farming and taking employment in industry or services, where exposure to microbial agents is lower. Standardized mortality ratios, with 95% confidence intervals, for 2,561 self-employed dairy farmers were estimated, considering the general population of Veneto, Italy, from 1970 to 1998 as the reference. Sixty-two lung cancer cases, whose information was checked against clinical records, were compared with 333 controls in a cohort-nested case-control study.

Remarks on Parallel Analysis.

We investigate parallel analysis (PA), a selection rule for the number-of-factors problem, from the point of view of permutation assessment. The idea of applying permutation test ideas to PA leads to a quasi-inferential, non-parametric version of PA which accounts not only for finite-sample bias but sampling variability as well. We give evidence, however, that quasi-inferential PA based on normal random variates (as opposed to data permutations) is surprisingly independent of distributional assumptions, and enjoys therefore certain non- parametric properties as well.