Use of hair colouring products and risk of multiple myeloma among US women.

OBJECTIVE: To evaluate the association between personal hair dye use and risk of multiple myeloma among women. METHODS: A population-based case-control study of 175 cases of multiple myeloma and 679 controls. Cases and controls were interviewed regarding the type and colour of hair colouring product used, age at first use, age use stopped, duration, and the frequency of use per year. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using unconditional logistic regression to compare never users with four exposure groups: all users, ever semi-permanent dye users, ever permanent dye users and dark permanent dye users (most frequent use). RESULTS: No association was found between ever reporting hair colouring product use and myeloma risk among all users (OR 0.8; 95% CI 0.5 to 1.1), semi-permanent dye users (OR 0.7; 95% CI 0.4 to 1.2), permanent dye users (OR 0.8; 95% CI 0.5 to 1.1) or dark permanent dye users (OR 0.8; 95% CI 0.5 to 1.3). There were no significant associations among women who used hair dyes before 30 years of age, started use before 1980, had >or=240 lifetime applications, or had used dark permanent dye for 28 or more years. CONCLUSION: No evidence of an association between hair colouring product use and myeloma risk was found. However, given the conflicting body of literature on hair colouring product use and risk of multiple myeloma, this question should be further evaluated in larger studies or consortia, and in high risk groups.

Time period compared to birth cohort in Connecticut incidence rates for twenty-five malignant neoplasms.

Out of necessity and convenience many reports on population-based rates for cancer are limited to analyses by time period of diagnosis, and just how often cohort effects are important in cancer data has not been fully explored. To address this question, Connecticut cancer incidence rates for the years 1940-79 were fitted to the model: Log (incidence rate) = constant + age effect + period effect + birth cohort effect + error term. Data for each cancer site and sex were categorized into 10-year intervals by time period and age group. Significance testing for the curvilinear effects (which are estimable functions) of age (A), period (P), and cohort (C) in the 44 data sets led to no clear choice of model for three data sets; an APC model for 20, an AP model for 7, and an AC model for 14. These choices were corroborated by the RA2 index. Limitations in the interpretation of the results were enumerated. Presentation of population-based cancer rates by implicitly assuming an AP model is valuable (e.g., for studying age distribution in different regions or for age-adjustment in examining international variation or time trends). However, the assumption of an AP model may often be incorrect, as was shown to be the case for most of these 44 data sets. The implications for monitoring trends and generating etiologic hypotheses were discussed in light of the results for cutaneous malignant melanoma and cancers of the cervix, breast, ovary, lung, and bladder.

Oral contraceptive use and fibrocystic breast disease with special reference to its histopathology.

The relationship between use of oral contraceptives and fibrocystic breast disease was examined in a hospital-based case-control study undertaken in New Haven, Connecticut, from 1977 to 1979. Particular emphasis was placed on the extent of epithelial atypia and other histopathologic characteristics found in the biopsy specimens from the cases. Women who had ever used oral contraceptives were at a somewhat decreased risk for fibrocystic disease as a whole. Cases with high atypia and controls had similar patterns of oral contraceptive use, whereas cases with low and intermediate atypia had less oral contraceptive use than controls. Cases with intermediate atypia reported the lowest oral contraceptive use. Subjects with biopsy specimens exhibiting gross cysts, microscopic cysts, or papillomatosis were about 50% less likely to have used oral contraceptives than controls.

Risk factors for fibrocystic breast disease and its histopathologic components.

The relationship between various sociodemographic, reproductive, and other factors to the occurrence of fibrocystic breast disease was evaluated in a case-control study undertaken at five Connecticut hospitals from 1979 to 1981. The study groups comprised 590 women with biopsy-proven fibrocystic breast disease and 1,018 women with other surgical conditions. Among the premenopausal women, multivariate analysis suggested that high socioeconomic status, Jewish religion, low parity, a history of benign breast disease, a history of breast cancer in the mother or a sister, and low Quetelet index were associated with increased odds ratios (OR) for fibrocystic breast disease. Similar analysis for the postmenopausal women revealed increased OR for women with high socioeconomic status, a late age at menopause, and a history of benign breast disease. Current smokers as well as those who had had a tubal sterilization had significantly reduced odds of fibrocystic disease. There was no convincing evidence of linear trends according to degree of epithelial atypia for any of the variables considered. Although some variation in the OR emerged in the analysis according to selected histologic components, the results provided little evidence that women with biopsy specimens exhibiting gross cysts, sclerosing adenosis, papillary hyperplasia, or papillomatosis showed epidemiologic similarities with breast cancer patients.

Exogenous estrogens and other factors in the epidemiology of breast cancer.

In a hospital-based case-control study of the epidemiology of breast cancer undertaken in Connecticut from 1977 to 1979, there was no evidence of an increase in risk for breast cancer among women who had used oral contraceptives or estrogen-replacement therapy. In fact, there was some suggestion of a decrease in risk for breast cancer with increasing length of use of oral contraceptives. Higher than average risks were found among women who had never give birth to a child, women with a late age at menopause, women, with an early age at menarche, women who had given birth to their first child at a relatively late age, women with previous benign breast disease, and women with a history of breast cancer in a sister or mother. Heavy women were at high risk for premenopausal breast cancer. The association between heaviness and postmenopausal breast cancer was strongest among women who had had their last menstrual period more than 5 years before the diagnosis of breast cancer.

Differences in breast cancer risk factors according to the estrogen receptor level of the tumor.

One hundred and forty-eight postmenopausal breast cancer cases and 585 postmenopausal controls were included in an investigation of whether various risk factors for breast cancer are associated with the level of estrogen (E) receptor (ER) protein in the tumor. In an intracase analysis, the tumor ER level was positively associated with nulliparity, late age at first live birth, a history of benign breast disease, and having breast-fed at least 1 child and was negatively associated with previous use of E replacement therapy. A case-control analysis suggested that the first three variables, established risk factors for breast cancer, are associated with an increased risk for malignant breast tumors that are ER-positive but not for those that are ER-negative. This analysis did not provide a clear interpretation of the findings in the intracase comparisons with regard to prior breast-feeding and the use of E replacement therapy.

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene and polychlorinated biphenyls and breast cancer: combined analysis of five U.S. studies.

BACKGROUND: Environmental exposure to organochlorines has been examined as a potential risk factor for breast cancer. In 1993, five large U.S. studies of women located mainly in the northeastern United States were funded to evaluate the association of levels of 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE) and polychlorinated biphenyls (PCBs) in blood plasma or serum with breast cancer risk. We present a combined analysis of these results to increase precision and to maximize statistical power to detect effect modification by other breast cancer risk factors. METHODS: We reanalyzed the data from these five studies, consisting of 1400 case patients with breast cancer and 1642 control subjects, by use of a standardized approach to control for confounding and assess effect modification. We calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs) by use of the random-effects model. All statistical tests were two-sided. RESULTS: When we compared women in the fifth quintile of lipid-adjusted values with those in the first quintile, the multivariate pooled OR for breast cancer associated with PCBs was 0.94 (95% CI = 0.73 to 1.21), and that associated with DDE was 0.99 (95% CI = 0.77 to 1.27). Although in the original studies there were suggestions of elevated breast cancer risk associated with PCBs in certain groups of women stratified by parity and lactation, these observations were not evident in the pooled analysis. No statistically significant associations were observed in any other stratified analyses, except for an increased risk with higher levels of PCBs among women in the middle tertile of body mass index (25-29.9 kg/m(2)); however, the risk was statistically nonsignificantly decreased among heavier women. CONCLUSIONS: Combined evidence does not support an association of breast cancer risk with plasma/serum concentrations of PCBs or DDE. Exposure to these compounds, as measured in adult women, is unlikely to explain the high rates of breast cancer experienced in the northeastern United States.

Time trends of non-Hodgkin's lymphoma: are they real? What do they mean?

Factors that need to be considered in the analysis of time trends in disease incidence are age, year of diagnosis, and birth cohort. When these are included in a log-linear model, a nonidentifiability problem arises from the linear dependence among these three time factors so that only specified functions of the parameters can be unambiguously determined. One of these invariant functions is the drift or the sum of the period and cohort trend. Non-Hodgkin's lymphoma incidence rates from Connecticut for the period 1935-1989 were analyzed for males and females. In addition to an age effect, both period and cohort significantly improved the fit of the model. The estimated drift shows that there has been a 10.3% increase in risk every 5 years since 1965 for females and 9.2% for males. It is unlikely that a trend of this magnitude can be attributed entirely to data artifact.

Pulse pressure and risk for myocardial infarction and heart failure in the elderly.

OBJECTIVES: We sought to determine whether pulse pressure (PP), a measure of arterial stiffness, is an independent predictor of the incidence of coronary heart disease (CHD), congestive heart failure (CHF) and overall mortality among community-dwelling elderly. BACKGROUND: Current hypertension guidelines classify cardiovascular risk on the basis of elevated systolic blood pressure (SBP) or diastolic blood pressure (DBP) without considering their combined effects. Recent studies suggest that PP is a strong predictor of cardiovascular end points, but few data are available among community elderly. METHODS: The study sample included 2,152 individuals age > or =65 years, who were participants in the Established Populations for Epidemiologic Study of the Elderly program, free of CHD and CHF at baseline and still alive at one year after enrollment. Blood pressure was measured at baseline. Incidence of CHD, incidence of CHF and total mortality were monitored in the following 10 years. RESULTS: There were 328 incident CHD events, 224 incident CHF events and 1,046 persons who died of any cause. Pulse pressure showed a strong and linear relationship with each end point. After adjusting for demographics, comorbidity and CHD risk factors, a 10-mm Hg increment in PP was associated with a 12% increase in CHD risk (95% confidence interval [CI], 2% to 22%), a 14% increase in CHF risk (95% CI, 5% to 24%), and a 6% increase in overall mortality (95% CI, 0% to 12%). While SBP and mean arterial pressure (MAP) also showed positive associations with the end points, PP yielded the highest likelihood ratio chi-square. When PP was entered in the model in conjunction with other blood pressure parameters (SBP, DBP, MAP or hypertension stage, respectively), the association remained positive for PP but became negative for the other blood pressure variables. The effect of PP persisted after adjusting for current medication use and was present in normotensive individuals and individuals with isolated systolic hypertension but not in individuals with diastolic hypertension. CONCLUSIONS: Elevated PP is a powerful independent predictor of cardiovascular end points in the elderly.