selected exogenous agents in the etiology of head and neck cancer. The factors studied were tobacco smoking, alcohol intake, the use of moist oral snuff, dietary

Objectives-This community based casereferent study was initiated to investigate aetiological factors for squamous cell carcinoma of the upper gastrointestinal tract. Methods-The study was based on all Swedish men aged 40-79 living in two regions of Sweden during 1988-90. Within that base, eVorts were made to identify all incident cases of squamous cell carcinoma of the oral cavity, oropharynx and hypopharynx, larynx, and oesophagus. Referents were selected as a stratified (age, region) random sample of the base. The response was 90% among cases and 85% among referents. There were 545 cases and 641 referents in the final study group. The study subjects were interviewed about several lifestyle factors and a life history of occupations and work tasks. The exposure to 17 specific agents were coded by an occupational hygienist. The relative risk (RR) of cancer was calculated by logistic regression, standardising for age, geographical region, and alcohol and tobacco consumption. Results-Exposure to asbestos was associated with an increased risk of laryngeal cancer, and a dose-response relation was present. The RR was 1.8 (95% confidence interval (95% CI) 1.1 to 3.0) in the highest exposure group. More than eight years of exposure to welding fumes was associated with an increased risk of pharyngeal cancer (RR 2.3 (1.1 to 4.7)), and laryngeal cancer (RR 2.0 (1.0 to 3.7)). There were indications of a dose-response for duration of exposure. Associations were also found for high exposure to polycyclic aromatic hydrocarbons (PAHs) and oesophageal cancer, RR 1.9 (1.1 to 3.2). Exposure to wood dust was associated with a decreased risk of cancer at the studied sites. Conclusions-Some of the present findings confirm known or suspected associations-such as asbestos and laryngeal cancer. The study indicates that welding may cause an increased risk of pharyngeal as well as laryngeal cancer. The findings corroborate an association between exposure to PAHs and oesophageal cancer. (Occup Environ Med 1998;55:393-400)

In a population-based case-control study carried out in Sweden in 1982-1984, the authors examined the association of pancreatic cancer with several dietary factors, coffee, alcohol, and tobacco. Analyses were based on 99 cases, 138 population controls, and 163 hospital controls. The cases were persons aged 40-79 years diagnosed with cancer of the exocrine pancreas at three surgical departments in Stockholm and Uppsala. The risk increased with higher consumption frequency of fried and grilled meat in the comparison with each series of controls (e.g., relative risk (RR) = 1.7 (90% confidence interval (CI) = 1.1-2.7) for weekly intake and RR = 13.4 (90% CI = 2.4-74.7) for almost daily intake, in the comparison with population controls). Furthermore, associations were found with other fried or grilled foods, but not with meat other than fried or grilled. The risk also increased with the intake of margarine (e.g., RR = 9.7 (90% CI = 3.1-30.2) for 15+ g of margarine on a slice of bread, in the comparison with population controls). In contrast, no excess risk was associated with high intake of butter. A low risk was associated with frequent consumption of fruits and vegetables, particularly carrots (RR = 0.3 (90% CI = 0.2-0.7)) and citrus fruits (RR = 0.5 (90% CI = 0.3-0.9)) for almost daily intake. No consistent associations were found with coffee, artificial sweeteners or alcohol consumption, but a threefold increase in risk was associated with smoking at least one pack of cigarettes per day.

In a population-based case-referent study of urothelial cancer in Stockholm during 1985-87, information was obtained from 78% of 418 identified cases and 77% of 511 selected referents. The relative risk (with 95% confidence interval) for intake of vitamin A supplements was 0.5 (0.2-1.0), with a dose-response relationship with increasing frequency of consumption. Increased risks of urothelial cancer were seen for several fried foods, for example fried meat [relative risk 1.4 (1.0-1.8) for weekly intake] and fried potatoes [relative risk 1.6 (1.1-2.6) for weekly intake]. Subjects with a high intake of fried foods, as defined by a collapsed variable, had a relative risk of 2.4 (1.4-4.2). A dose-response relationship was also seen with an increasing average daily intake of fat [relative risk 1.7 (1.0-2.8) in the highest quintile], but adjusting for fried foods decreased the relative risk, and it is uncertain whether the adjustment allowed for residual confounding. No association was noted for meat other than fried, but the analysis was based on small numbers.

The association between physical job activity and colon cancer was examined in a 19-year follow-up study of 1.1 million Swedish men. The relative risk (RR) of colon cancer in men employed in sedentary occupations was estimated at 1.3 (1.2-1.5, 90% confidence interval), with the highest risk for the transverse colon including flexures (RR = 1.6) and the lowest risk for the sigmoid (RR = 1.2). The relative risk for rectal cancer was not elevated. Age, population density, and social class did not confound the relative risk and were controlled for, whereas marital status and geographic region did not. Furthermore, food habits and physical activity during leisure time were examined in the same occupations in another sample and it was judged unlikely that confounding from these factors could explain the association.

Follow-up studies are needed to determine how long the improved compliance persists, but anyone considering setting up an education and tailoring programme should recognise the extent to which therapeutic efforts are wasted because of non-compliance.

No abstract

A case-control study of cutaneous malignant melanoma (CMM) was based on 523 incident cases and 505 age- and sex-matched controls selected from the general population. The purpose was to investigate the relative risk of developing CMM associated with different sun habits and indicators of pigmentation, such as skin type, eye colour and hair colour. Compared to people with black hair, blonde subjects had a relative risk of 74.4 (95% confidence interval, 45.8-120.8). Associations with skin type and eye colour were considerably weaker. Relative risks of about 1.5-2.5 were found for certain sun habits. The results suggest that in a population of Caucasian origin with a predominantly fair complexion, pigmentary status characterized by hair colour is a far more important aetiological factor than sun habits.