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Active smoking has little or no effect on breast cancer risk but some investigators have suggested that passive smoking and its interaction with active smoking may be associated with an increased risk. In a population based case-control study of breast cancer in women aged 36-45 years at diagnosis, information on active smoking, passive smoking in the home, and other factors, was collected at interview from 639 cases and 640 controls. Women were categorised jointly by their active and passive smoking exposure. Among never smoking controls, women who also reported no passive smoking exposure were significantly more likely to be nulliparous and to be recent users of oral contraceptives. Among those never exposed to passive smoking, there was no significant association between active smoking and breast cancer, relative risk (RR) of 1.12 (95% confidence interval (CI) 0.72-1.73) for past smokers and RR of 1.19 (95% CI 0.72-1.95) for current smokers, nor was there an association with age started, duration or intensity of active smoking. Compared with women who were never active nor passive smokers, there was no significant association between passive smoking in the home and breast cancer risk in never smokers, RR of 0.89 (95% CI 0.64-1.25), in past smokers, RR of 1.09 (95% CI 0.75-1.56), or in current smokers, RR of 0.93 (95% CI 0.67-1.30). There was no trend with increasing duration of passive smoking and there was no heterogeneity among any of the subgroups examined. In this study, there was no evidence of an association between either active smoking or passive smoking in the home and risk of breast cancer. [ABSTRACT FROM AUTHOR]

We examined the relationship between body fatness, sports participation and breast cancer risk in 1560 premenopausal cases and 1548 controls, from three related population-based case–control studies in the UK. Half of the women with breast cancer were aged less than 36 years at diagnosis. Women who perceived themselves as plump at age 10 years had a relative risk of 0.83 (95% confidence interval 0.69–0.99, P=0.03) as compared with those who perceived themselves as thin. Self-reported obesity compared with leanness at diagnosis was associated with a relative risk of 0.78 (95% confidence interval 0.56–1.06, P=0.11). Women who reported having been plump at age 10 years and overweight or obese at diagnosis had a relative risk of 0.75 (95% confidence interval 0.56–1.01, P=0.06) as compared with those who reported being thin at age 10 years and at diagnosis. Findings for three related measures of body fatness suggested that obesity is associated with a reduced risk of premenopausal breast cancer. There was no association between sports participation and breast cancer risk in these premenopausal women. The relative risk for spending an average of more than 1 h per week in sports compared with less from ages 12 to 30 years was 1.00 (95% CI 0.86–1.16, P=0.98).British Journal of Cancer (2005) 93, 817–824. doi:10.1038/sj.bjc.6602758 www.bjcancer.com Published online 13 September 2005 [ABSTRACT FROM AUTHOR]

We report results on risk factors for invasive squamous cell and adenocarcinomas of the cervix in women aged 20-44 years from the UK National Case-Control Study of Cervical Cancer, including 180 women with adenocarcinoma, 391 women with squamous cell carcinoma and 923 population controls. The risk of both squamous cell and adenocarcinoma was strongly related to the lifetime number of sexual partners, and, independently, to age at first intercourse. The risk of both types of cervical cancer increased with increasing duration of use of oral contraceptives, and this effect was most marked in current and recent users of oral contraceptives. The risk of squamous cell carcinoma was associated with high parity and the risk of both squamous cell and adenocarcinoma increased with early age at first birth. Long duration smoking (20 or more years) was associated with a two-fold increase in the risk of squamous cell carcinoma, but smoking was not associated with the risk of adenocarcinoma. Further studies are needed to confirm the suggestion from this and other studies of differences in risk related to smoking between squamous cell and adenocarcinomas of the cervix. [ABSTRACT FROM AUTHOR]

Three groups of men and women employed at a Rochdale asbestos textile factory have been followed to 30 June 1983 and their mortality compared with that expected at national and Rochdale rates, i.e. (i) 145 men first employed before 1933 who had served 20 yr or more in scheduled areas, (ii) 283 women first employed in 1933 or later who had served ten or more years in scheduled areas, and (iii) a principal cohort of 3211 men first employed between 1933 and 1974. Systematic measurements of the ambient pollution in the workplace have been made since 1951 either in terms of particles ml or of fibres (of specified size) ml and estimates have been made of the average concentration of particles (or fibres) to which individual members of the principal cohort were exposed. From these data estimates have been made of the quantitative relationship between ambient exposure and mortality from lung cancer and mesothelioma. These results, together with other published data, suggest that the lung cancer rate among chrysotile textile workers is approximately doubled following a cumulative exposure of 100 fibre ml yr, irrespective of age at first exposure. Chrysotile asbestos was used in the factory throughout, but some crocidolite (approx. 5.0%) was used between 1932 and 1968 and this may have contributed, perhaps substantially, to the observed mesothelioma risk. For the purpose of risk prediction we have rather arbitrarily assumed that the mesothelioma risk caused by a similar concentration of pure chrysotile would have been roughly half that observed in this factory. This implies that 35 yr chrysotile exposure at an average concentration of 1 fibre ml might eventually cause mesothelioma in about one worker in 200 if exposure began at age 20, although the risk would be substantially lower if exposure began later in life. If enforcement of the current U.K. control limit for chrysotile of 0.5 fibre ml results in an average level of 0.25 fibre ml in the workplace, these estimates suggest that the risk of eventually developing asbestos-related lung cancer or mesothelioma to a man first employed at age 20 who works in the asbestos textile industry for 35 yr may be about 0.8%. This prediction is of doubtful accuracy, however, as the exposure data were derived largely from static particle counts and the correlation between particle and fibre counts is poor. [ABSTRACT FROM PUBLISHER]

Background: Oral contraceptives were introduced almost 50 years ago, and over 100 million women currently use them. Oral contraceptives can reduce the risk of ovarian cancer, but the eventual public-health effects of this reduction will depend on how long the protection lasts after use ceases. We aimed to assess these effects.Methods: Individual data for 23,257 women with ovarian cancer (cases) and 87,303 without ovarian cancer (controls) from 45 epidemiological studies in 21 countries were checked and analysed centrally. The relative risk of ovarian cancer in relation to oral contraceptive use was estimated, stratifying by study, age, parity, and hysterectomy.Findings: Overall 7308 (31%) cases and 32,717 (37%) controls had ever used oral contraceptives, for average durations among users of 4.4 and 5.0 years, respectively. The median year of cancer diagnosis was 1993, when cases were aged an average of 56 years. The longer that women had used oral contraceptives, the greater the reduction in ovarian cancer risk (p<0.0001). This reduction in risk persisted for more than 30 years after oral contraceptive use had ceased but became somewhat attenuated over time-the proportional risk reductions per 5 years of use were 29% (95% CI 23-34%) for use that had ceased less than 10 years previously, 19% (14-24%) for use that had ceased 10-19 years previously, and 15% (9-21%) for use that had ceased 20-29 years previously. Use during the 1960s, 1970s, and 1980s was associated with similar proportional risk reductions, although typical oestrogen doses in the 1960s were more than double those in the 1980s. The incidence of mucinous tumours (12% of the total) seemed little affected by oral contraceptives, but otherwise the proportional risk reduction did not vary much between different histological types. In high-income countries, 10 years use of oral contraceptives was estimated to reduce ovarian cancer incidence before age 75 from 1.2 to 0.8 per 100 users and mortality from 0.7 to 0.5 per 100; for every 5000 woman-years of use, about two ovarian cancers and one death from the disease before age 75 are prevented.Interpretation: Use of oral contraceptives confers long-term protection against ovarian cancer. These findings suggest that oral contraceptives have already prevented some 200,000 ovarian cancers and 100,000 deaths from the disease, and that over the next few decades the number of cancers prevented will rise to at least 30,000 per year. [ABSTRACT FROM AUTHOR]