Lung cancer and related risk factors: an update of the literature

At the present time, lung cancer is the leading cause of cancer-related death in males. Diagnostic difficulty makes detection complicated and this, in conjunction with the low survival rate, renders the disease a serious health problem. In-depth knowledge of associated risk factors is therefore called for, in order to prevent or at least reduce the appearance of lung cancer and to open new avenues of research. Although the disease has a multicausal aetiology, tobacco accounts for 85-90% of all cases. This paper reviews the current situation, dividing the risk factors, for study purposes, into two groups; intrinsic (non-modifiable) and extrinsic (modifiable).

Exposure to residential radon and lung cancer in Spain: a population-based case-control study

Although high radon concentrations have been linked to increased risk of lung cancer by both experimental studies and investigations of underground miners, epidemiologic studies of residential radon exposure display inconsistencies. The authors therefore decided to conduct a population-based case-control study in northwest Spain to determine the risk of lung cancer associated with exposure to residential radon. The study covered a total of 163 subjects with incident lung cancer and a population sample of 241 cancer-free subjects since 1992-1994. Odds ratios for radon were estimated using logistic regression adjusted for sex, age, lifetime tobacco use, family history, and habitat. The adjusted odds ratios for the second, third, and fourth quartiles of radon (breakpoints: 37.0, 55.2, and 148.0 Bq/m(3)) were 2.73 (95% confidence interval (CI): 1.12, 5.48), 2.48 (95% CI: 1.29, 6.79), and 2.96 (95% CI: 1.29, 6.79), respectively. An additive synergic effect between radon and tobacco was found. The results from this study suggest that, even at concentrations far below official guideline levels, radon may lead to a 2.5-fold rise in the risk of lung cancer. Furthermore, the synergy found between smoking and radon may prove useful when it comes to drafting public health recommendations.

Diet and lung cancer: a new approach

Lung cancer is one of major public health problems facing the world today, owing to the high incidence of the disease and its poor prognosis. Although the principal cause of lung cancer is tobacco use, smokers find it extremely difficult to quit the habit. Hence, there is a need to take action targeted at other risk factors for this disease. One such factor is diet, which is known to be able to raise or lower the risk of lung cancer. This paper seeks to complement other reviews in the field and to shed more light both on the influence that dietary factors may have upon the occurrence of this neoplasm and on the causes of this possible effect.

[2 methods for the study of differential mortality based on sex: rates ratio and orthogonal regression]

Sex mortality differential is studied for all the causes of death, in La Coruña (Galicia, Spain), according to geographic area, zone (urban, semiurban and countryside) and decade (1961-1970 y 1971-1980). Two study methods are compared: a) Rate ratio (with direct age-adjusted rates); and b): Differential (Dj) between observed rate (M) and expected rate (M), for male mortality, according to female level (orthogonal regression model). t-Student-Fisher tests have been used to compare an observed mean and a theoretic one, and to compare two observed means, with independent data. An increase in male overmortality is found, from one to the other decade (112.9% to 117.0%), confirmed by orthogonal method: respectively 5.38 deaths every 100,000 and 16.81 deaths. This over-mortality is more frequent in the urban areas, while inframortality appears mainly in countryside areas. Furthermore, male overmortality increases in urban zones and decreases in semiurban and rural zones.