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The hypothesized association between breast cancer and circadian disruption was evaluated in the Electromagnetic Fields and Breast Cancer on Long Island Study. Participants included 576 women with breast cancer diagnosed from August 1996 to June 1997 and 585 population-based controls (87% and 83% participation rates, respectively) aged < 75 years and living in the same Long Island, New York, home for > or = 15 years. An in-person interview ascertained light-at-night exposure histories through shift work (previous 15 years) and at home (previous 5 years). Odds ratios and 95% confidence intervals were estimated by unconditional multivariate logistic regression. Breast cancer was not associated with overall shift work (odds ratio (OR) = 1.04, 95% confidence interval (CI): 0.79, 1.38) or evening shift work (OR = 1.08, 95% CI: 0.81, 1.44). However, overnight shift workers were at lower risk than women never working shifts (OR = 0.55, 95% CI: 0.32, 0.94). Women who frequently turned on lights at home during sleep hours (> or = twice/week and > or = twice/night) had increased risks (OR = 1.65, 95% CI: 1.02, 2.69). The latter results suggest positive associations with residential light-at-night exposure, or they could reflect response biases. Furthermore, overall and evening shift work were not significant factors, and analyses of overnight shift workers yielded reduced risk estimates. The study thus provides mixed evidence for the light-at-night hypothesis.

Background: Exposure to electromagnetic fields (EMF) has been hypothesized to increase the risk of breast cancer by inhibiting the normal nocturnal rise in melatonin levels., Methods: Information on electric blanket use was collected in a large, 2-stage, population-based, case-control investigation of breast cancer, The Long Island Breast Cancer Study Project (LIBCSP) and the EMF and Breast Cancer on Long Island Study (EBCLIS). The LIBCSP used a comprehensive questionnaire, including questions about electric appliance use, with responses available on 1354 cases diagnosed between mid-1996 and mid-1997 and 1426 control subjects. EBCLIS enrolled 576 cases and 585 control subjects who had participated in the LIBCSP and who had lived in their current homes for at least 15 years. EBCLIS participants were interviewed to obtain additional information on EMF exposures, including detailed questions on electric blanket use., Results: Analyses of both the EBCLIS and the LIBCSP groups showed no association with breast cancer for ever-use of electric blankets, current or former use, use directly on the body, or use throughout the night in either pre- or postmenopausal women (range of adjusted odds ratios for ever vs. never use: 0.9-1.2). Furthermore, there was no trend in risk with increased duration of use, frequency of use, or other indicators of more intense exposure to EMF. Electric blanket use was not associated with hormone receptor status of the tumor., Conclusions: The results of this large investigation are consistent with those of most previous studies, and do not support the hypothesis that electric blanket use is associated with increased breast cancer risk.

The Electromagnetic Fields and Breast Cancer on Long Island Study (EBCLIS) is a large population-based case-control study investigating possible associations between magnetic fields and breast cancer, and includes a comprehensive set of in-home measurements. We investigated the reproducibility of wire codes, their relation to 24-h measurements of residential magnetic fields, and potential influences, such as housing characteristics, in homes of the 1161 EBCLIS participants. Replicate wire coding was performed in homes originally categorized as having very high current configurations (VHCC) in the Wertheimer-Leeper (W-L) wire coding scheme, and a random sample of other homes (235 residences). Reproducibility was very high, with a kappa statistic of 0.83 (95% confidence interval (CI)=0.77-0.89) for the five-category W-L wire codes and 0.91 (95% CI=0.86-0.95) for the three-category Kaune-Savitz (K-S) codes. As levels of W-L and K-S wire codes increased, the mean and median 24-h levels of broadband and harmonic fields in the residences also increased, indicating an association between wire codes and magnetic fields measurements. Regions of Long Island with the highest percentage of homes built before 1950 had the highest percentage of higher current configuration homes, as well as the highest average 24-h broadband and harmonic measurements. Adjustment for age of the home and region did not affect the relation between wire codes and measured magnetic fields. Our results indicate that: (a). a high reproducibility in wire coding was achieved, (b). wire codes were correlated with magnetic fields, and (c). wire code levels were related to the age of the home. The high level of reproducibility suggests that, in our case-control analyses, there will be minimal bias due to misclassification of wire code categories. Results also suggest that wire codes are a proxy measure, to some degree, for current in-home magnetic field measurements in this study.

The EMF and Breast Cancer on Long Island Study (EBCLIS) was a case-control study designed to evaluate the possible association between exposure to electromagnetic fields (EMFs) and breast cancer. Eligible women were participants in the population-based Long Island Breast Cancer Study Project, were under 75 years of age at enrollment, were residentially stable, and were identified between August 1, 1996, and June 20, 1997. Of those eligible, 576 cases and 585 controls participated in EBCLIS (87% and 83%, respectively). In-home data collection included various spot and 24-hour EMF measurements, ground-current magnetic field measurements, wire mapping of overhead power lines servicing the home, and an interview. Odds ratios and 95% confidence intervals were based on multivariate logistic regression analyses. All odds ratios were close to 1 and nonsignificant. For the highest quartile of 24-hour EMF measurements, the odds ratio was 0.97 (95% confidence interval (CI): 0.69, 1.37) in the bedroom and 1.09 (95% CI: 0.78, 1.51) in the most lived-in room. For the highest exposure category of ground-current measurements, the odds ratio was 1.13 (95% CI: 0.88, 1.44) in the bedroom and 1.08 (95% CI: 0.85, 1.38) in the most lived-in room. These and other EBCLIS results agree with other recent reports of no association between breast cancer and residential EMF exposures.

The accurate and valid measurement of personal exposure to magnetic fields poses a major challenge for epidemiologic studies. When considering the various methods to assess exposure, it is unclear which measures are most relevant for studies of human disease, if any. Given these uncertainties, the Electromagnetic Fields and Breast Cancer on Long Island Study (EBCLIS) undertook a pilot study to develop the data collection protocol for a case-control study of breast cancer and magnetic fields. The pilot study used and compared various methods to assess residential exposures to magnetic fields, and related these measures to personal exposures. It included 31 women without breast cancer (mean age, 63+/-7 yr) who lived in their present homes for at least 15 yr. The pilot study consisted of an in-home interview, spot and 24-h magnetic field waveforms and broadband recordings, ground currents, wire coding, and personal 24-h broadband measurements. From the regression analyses, the model that best predicted personal magnetic field exposures included 24-h measurements in the bedroom and in the most lived-in room; as well as ground current test loads taken at the center of this most lived in room (r(2)=86%). The addition of other variables in this regression model yielded only small and nonsignificant increases in r(2). As a direct result of this pilot, EBCLIS will include ground current measurements in its protocol, which have not previously been collected as part of an epidemiologic study. Ground currents may be important because they may be richer in 180 Hz components than are the other currents in a power system. EBCLIS will have the opportunity to examine the ground-current hypothesis in the context of female breast cancer., (Copyright 1999 Wiley-Liss, Inc.)

Objective: The purpose of the study is to estimate incidence and progression rates of cortical and posterior subcapsular (PSC) opacities in the Longitudinal Study of Cataract (LSC)., Design: An epidemiologic study of the natural history of lens opacities in a clinic-based population., Participants: The LSC was based on 764 participants in an earlier case-control study of lens opacities., Main Outcome Measures: Baseline data, collected until 1988, included color slit and retroillumination photographs. The same data were collected at follow-up visits from 1989 to 1993. The Lens Opacities Classification System III (LOCS III) was used to assess lens changes between baseline and follow-up photographs. The product-limit method was used to estimate the incidence and progression rates., Results: After 5 years of follow-up, the incidence rates for developing cortical and PSC opacities were 7.7% and 4.3%, respectively. The progression rate of pre-existing cortical opacities was 16.2% after 5 years, and was twice as high as the incidence rate. The progression of pre-existing PSC opacities was much higher, and reached 55.1% after 5 years of follow-up. The incidence of newly developed cortical or PSC opacities increased with age. The incidence of PSC opacities also increased when coexisting opacities were present at baseline., Conclusions: After 5 years, 1 in every 13 patients developed new cortical opacities, and 1 in 24 developed new PSC opacities. The 5-year progression rates for cortical and PSC opacities were much higher than the incidence rates. These results can be used to estimate the rate of cortical and PSC changes in similar populations.

Background: Alcohol use is associated with breast cancer in many epidemiological studies. Most, however, have measured risk from recent consumption patterns, and only a few include analyses for duration of drinking or age that a woman started to drink. The authors studied the effect of these variables, as well as of recent alcohol consumption patterns, on breast cancer risk., Methods: Data from a large case-control study conducted in Long Island, New York from 1 January 1984 to 31 December 1986 were used. A total of 1214 women aged 20-79 years with incident breast cancer were interviewed. A control was selected for each case from driver's license files, and matched on age and county of residence. Alcohol consumption was measured as: ever versus never, grams of alcohol per day, age started drinking, and total years drinking., Results: After adjustment for breast cancer risk factors, the odds ratio for ever versus never drinking was 1.40 (95% confidence interval [CI] 1.09-1.79); odds ratios for > 0-5 and > or = 5 grams of alcohol use per day, as compared to nondrinkers, were 1.29 (95% CI: 1.00-1.65) and 1.46 (95% CI: 1.13-1.89), respectively. Age when drinking began was not related to breast cancer risk, but the greater the total years of drinking, up to 40 years (odds ratio 1.48, 95% CI: 1.13-1.93), the greater the risk. However, when grams per day and duration of drinking were simultaneously included in the multivariate model, duration was not important as a risk factor. This suggests that intensity of drinking may be the important factor for breast cancer risk. After covariate adjustment, risk from alcohol intake did not differ between pre- and postmenopausal women.

This case-control study evaluated risk factors for open-angle glaucoma (OAG) and high intraocular pressure (IOP), including systemic hypertension and its treatment, other systemic factors, familial, and demographic variables. The three study groups were based on masked ophthalmologic gradings of visual fields and fundus photographs, as well as tonometry. The OAG group (n = 122) had OAG field defects, IOP > 21 mmHG, and cup-disc ratios > or = 0.5 and/or evidence of glaucoma disc damage. The ocular hypertensives (n = 108) had no field defects, IOP > 21 mmHg and normal discs. The controls (n = 190) had no field defects, IOP < 21 mmHg and normal discs. The data collection protocol included a standardized interview and measurements. Medical history was confirmed by contacting the primary care physicians (89% response from physicians). Study groups were compared by polychotomous logistic regression analyses. Men were more likely to have OAG and less likely to have ocular hypertension. Systemic hypertension was more frequent in ocular hypertensives (Odds Ratio = 2.36); high diastolic pressure was associated with OAG and ocular hypertension (OR = 2.13 and 2.21, respectively). Treatment for systemic hypertension was unrelated to OAG risk. Low perfusion pressures (blood pressure-IOP differences) were strongly associated with OAG and ocular hypertension, a finding that could be due to the high IOP in these groups. A family history of glaucoma was more frequent in OAG (OR = 3.08) and ocular hypertension (OR = 2.38) than in controls. Alcohol consumption was related to ocular hypertension (OR = 2.32). No other associations were significant. The results confirm an association of blood pressure with intraocular pressure. Since the OAG and ocular hypertensive groups had similar blood pressure results, an independent effect of blood pressure on OAG was not substantiated.

Purpose: To estimate incidence and progression rates of nuclear opacities in the Longitudinal Study of Cataract, an epidemiologic study of the natural history of all types of lens opacities., Methods: The Lens Opacities Classification System III was used to assess longitudinal changes between baseline and follow-up lens photographs for the 764 Longitudinal Study of Cataract participants. Baseline data, collected until December 1988 as part of a case-control study, included color slit, retroillumination, and Scheimpflug photographs. The same data were collected by the longitudinal Study of Cataract at four subsequent visits at yearly intervals., Results: Among patients free of nuclear opacities at baseline, the incidence of new opacities was 6% after 2 years and 8% after 5 years of follow-up. The progression of pre-existing nuclear opacities was much higher. After 2 years, nuclear opacities had progressed in more than one third of the patients with pre-existing opacities; after 5 years, almost half had progressed. Older age was significantly related to higher incidence of new nuclear opacities, but not to progression of pre-existing opacities. Patients with other opacity types had higher nuclear incidence and progression rates., Conclusions: In this clinic-based, older-patient population, new nuclear opacities developed in less than one tenth of the patients after 5 years of follow-up. In contrast, almost one half of the patients with pre-existing opacities had worsened after 5 years. These estimated rates can be used to plan intervention or other studies of nuclear changes in similar populations.

The relationship between oestrogen replacement therapy and breast cancer risk was examined based on data obtained from a population-based case-control study of breast cancer on Long Island, New York, USA. Cases were defined as female residents of two Long Island counties, aged 20-79, who were diagnosed with breast cancer between 1 January 1984 and 31 December 1986. Age- and county-matched controls were selected from driver's licence files. Among all postmenopausal women, there was no significant association between ever-use of hormones to treat menopausal symptoms and breast cancer risk. There was also no significant positive association in any subgroup defined by type of menopause (natural, hysterectomy with at least one ovary intact, bilateral oophorectomy) or age at menopause. Additionally, there was no increasing trend in risk with duration of use either overall or in any subgroup, nor was there an effect at any interval since last use. A significant elevation in risk was observed in women with 10-19 years since first exposure, which was concentrated in women with a natural menopause or hysterectomy with at least one ovary remaining, and women aged > 45 at menopause. Results of logistic regression analysis revealed no important confounding by any of several established breast cancer risk factors. However, a significant interaction was observed between body mass index (BMI) and oestrogen use, with an effect of oestrogen use being seen only in the thinnest tercile. Although biologically plausible explanations for this finding exist, the effect of chance cannot be ruled out.