Serum 25-hydroxyvitamin D and colon cancer: eight-year prospective study.

Blood samples taken in 1974 in Washington County, Maryland, from 25 620 volunteers were used to investigate the relation of serum 25-hydroxyvitamin D (25-OHD) with subsequent risk of getting colon cancer. 34 cases of colon cancer diagnosed between August, 1975, and January, 1983, were matched to 67 controls by age, race, sex, and month blood was taken. Risk of colon cancer was reduced by 75% in the third quintile (27-32 ng/ml) and by 80% in the fourth quintile (33-41 ng/ml) of serum 25-OHD. Risk of getting colon cancer decreased three-fold in people with a serum 25-OHD concentration of 20 ng/ml or more. The results are consistent with a protective effect of serum 25-OHD on colon cancer.

Factors associated with past household exposure to tobacco smoke.

With data that were obtained in a private census in Washington County, Maryland, in 1963, the prevalence of household exposure to tobacco smoke was determined, and factors associated with passive smoke exposure were identified among 48,342 white adults. In 1963, 52% of men and 72% of women were exposed to smoke from others at home. Smokers of both sexes were more likely to live with other smokers than were nonsmokers. However, 30% of men who never smoked and 64% of women who never smoked lived with smokers. Marriage was a primary determinant of exposure for women but not for men, with 75% of married women who did not smoke exposed but only 38% of unmarried women who did not smoke exposed. Conversely, among men who did not smoke, exposure was more common among those who were not married than among those who were married. After control for other factors associated with exposure, exposure prevalence increased with years of school among men who did not smoke but decreased with years of school among women who did not smoke. Exposure prevalence also varied slightly with housing quality and location of residence. Smoking by spouse was an accurate reflection of household exposure for women but not for men; 88% of the exposure among women who did not smoke was contributed by the spouse, whereas only 62% of exposure among men who did not smoke was from the spouse.

Deaths from all causes in non-smokers who lived with smokers.

Mortality associated with passive smoking was evaluated in a 12-year study of 27,891 White adult smokers and 19,035 never smokers identified in 1963. Death rates were calculated using an estimate of the person-years at risk. Adjusted for age, marital status, education, and quality of housing, the estimated relative risks of death from all causes were 1.17 (approximate 95% confidence interval 1.01, 1.36) for men and 1.15 (1.06, 1.24) for women with passive exposure. These relative risks were similar to those for ex-smokers and for pipe or cigar smokers. Risks increased slightly with level of exposure. The relative risk from passive smoking was greatest for men under age 50 (RR = 2.09, 1.31-3.34). Risks from passive smoking were slightly elevated for several causes among men and women, and may be broader than those previously reported. On the other hand, these small nonspecific increases in death rates may reflect other characteristics of passive smokers that increase mortality.

Cigarette smoking and the risk of colorectal cancer in women.

Colorectal cancer incidence rates for smokers, nonsmokers living with smokers (i.e., passive smokers), and nonsmokers in smoke-free households were compared in a 12-year prospective study of 25,369 women who participated in a private census conducted in Washington County, MD, in 1963. Women who smoked had a decreased relative risk of colorectal cancer compared with the risk for nonsmokers (age-adjusted relative risk, 0.76; 95% confidence interval, 0.52-1.10). The risk for passive smokers was similar to that for smokers. The relative risks were significantly reduced for older women; relative risks were 0.42 for smokers and 0.66 for passive smokers over age 65. The data suggest that older women who smoke have a lower risk of colorectal cancer than nonsmokers. The effect may be mediated by an antiestrogenic effect of smoking.

Heart disease mortality in nonsmokers living with smokers.

A private census of Washington County, Maryland, in 1963 obtained information on smoking habits of all adults in the census, and death certificates of all residents who died in the next 12 years were coded for underlying cause of death and matched to the census. Among the white population aged 25 and over, 4,162 men and 14,873 women had never smoked. In this group, death rates from arteriosclerotic heart disease were significantly higher among men (relative risk (RR) = 1.31, 95% confidence interval (CI) 1.1-1.6) and women (RR = 1.24, 95% CI 1.1-1.4) who lived with smokers in 1963, after adjustment for age, marital status, years of schooling, and quality of housing. Among women, the relative risk increased significantly (p less than 0.005) with increasing level of exposure; among men, there was little evidence of a dose-response relation. The relative risks for nonsmokers who lived with smokers were greatest among both men and women who were younger than age 45 in 1963, but the number of deaths in these groups was small, and confidence intervals were broad. These results suggest a small but measurable risk for arteriosclerotic heart disease among nonsmokers who live with smokers.

Serum levels of retinol, beta-carotene, and alpha-tocopherol in older adults.

Levels of retinol, beta-carotene, and alpha-tocopherol were determined in the serum of 415 adults over age 35 years who had volunteered in 1974 to donate blood for cancer research in Washington County, Maryland. Males had higher levels of serum retinol, lower levels of beta-carotene, and only slightly lower levels of alpha-tocopherol than did females. No clear-cut association was noted with age. Smokers had decreased serum levels of beta-carotene. Vitamin supplementation was associated with higher serum levels. Persons taking medication for high blood pressure had higher levels of retinol and alpha-tocopherol, but lower levels of beta-carotene.

Serologic precursors of cancer. I. Prediagnostic serum nutrients and colon cancer risk.

A study was undertaken to determine whether prediagnostic serum levels of retinol, beta-carotene, vitamin E, and selenium are lower in colon cancer cases compared with matched, population-based controls. Sera were available from 25,802 participants of a serum collection campaign conducted in Washington County, Maryland in 1974. The authors identified from these participants 72 white colon cancer cases, who were first diagnosed with colon cancer during 1975-1983, and 143 white, living, cancer-free controls, matched to cases on the basis of age, sex, month of serum collection, and enumeration in a 1975 private census of Washington County. The mean values of serum nutrients in cases and controls, respectively, were 59.1 micrograms/dl and 61.8 micrograms/dl for retinol (p = 0.22), 32.9 micrograms/dl and 34.4 micrograms/dl for beta carotene (p = 0.52), 1.17 mg/dl and 1.27 mg/dl for vitamin E (p = 0.10), and 11.0 micrograms/dl and 11.5 micrograms/dl for selenium (p = 0.07). There were no consistent trends in the relative odds of colon cancer by quintiles of serum levels for any of the nutrients; however, a relative odds of 3.2 (95% confidence interval = 1.1-8.7) was found when persons in the four lowest quintiles of retinol were compared with those in the highest. No interactions with matching factors or between serum nutrients and no confounding effects of covariables were identified through conditional logistic regression analysis. The findings of this study do not support a strong association of low serum levels of retinol, beta-carotene, vitamin E, and selenium with an increased risk of subsequent colon cancer.

Sex hormone levels in serum in relation to the development of breast cancer.

In 1974, approximately 13,000 female residents of Washington County, Maryland, donated 15 ml of blood as part of a project to determine if certain serologic factors were related to the development of site-specific cancer. Sera were stored at -73 C. The present study reports the associations of serum levels of estrone, estradiol, estriol, androstenedione, progesterone, and testosterone with breast cancer among 17 premenopausal cases diagnosed 8-132 months after blood was drawn, and 39 postmenopausal cases diagnosed 6-72 months after blood was drawn. Each case was matched to four controls selected from the other serum bank donors. Matching factors were age, race, and time since last menstrual period. Cases and controls who were taking estrogen-containing preparations were excluded from this analysis. Sera were analyzed without knowledge of case-control status. Differences in levels of serum hormones between cases and controls were slight and not statistically significant.

Serum beta-carotene, vitamins A and E, selenium, and the risk of lung cancer.

We studied the relation of serum vitamin A (retinol), beta-carotene, vitamin E, and selenium to the risk of lung cancer, using serum that had been collected during a large blood-collection study performed in Washington County, Maryland, in 1974. Levels of the nutrients in serum samples from 99 persons who were subsequently found to have lung cancer (in 1975 to 1983) were compared with levels in 196 controls who were matched for age, sex, race, month of blood donation, and smoking history. A strong inverse association between serum beta-carotene and the risk of squamous-cell carcinoma of the lung was observed (relative odds, 4.30; 95 percent confidence limits, 1.38 and 13.41). Mean (+/- SD) levels of vitamin E were lower among the cases than the controls (10.5 +/- 3.2 vs. 11.9 +/- 4.90 mg per liter), when all histologic types of cancer were considered together. In addition, a linear trend in risk was found (P = 0.04), so that persons with serum levels of vitamin E in the lowest quintile had a 2.5 times higher risk of lung cancer than persons with levels in the highest quintile. These data support an association between low levels of serum vitamin E and the risk of any type of lung cancer and between low levels of serum beta-carotene and the risk of squamous-cell carcinoma of the lung.

Dog and cat ownership among suicides and matched controls.

In Washington County, Maryland, ownership of cats and/or dogs was compared among 48 residents who committed suicide in the years 1975-83 and 96 living controls matched to the suicides by race, sex, and date of birth. Another comparison used as controls persons of same race, sex, and age who died of causes other than suicide in the same year as the suicide. No material association between pet ownership and suicide was observed.

Causes of death in a widowed population.

Causes of death of widowed and married were compared in a nonconcurrent prospective study in Washington County, Maryland, which identified 4032 white persons aged 18 years and over who were enumerated in a 1963 nonofficial census and who became widowed between 1963 and 1974, and an equal number of married persons, each matched to a widowed person as to race, sex, year of birth, and geography of residence. Underlying causes of death were obtained from the death certificates of those who had died. Deaths from infectious diseases, accidents, and suicide were significantly higher than expected among widowed males, and deaths from cirrhosis of the liver were significantly higher than expected among widowed females. The similarity in causes of death of the widowed and their predeceased spouses was no greater than expected to occur by chance. There was no indication that widowed males or females suffering from chronic diseases, as defined by duration of underlying causes of death being two years or more, suffered earlier mortality after bereavement than others.

Factors associated with mortality after widowhood.

A non-concurrent prospective study in Washington County, Maryland identified 4,032 (1,204 male, 2,828 female) White persons aged 18 and over who were enumerated in a 1963 non-official census and who became widowed between 1963 and 1974, and an equal number of married persons, each matched to a widowed as to race, sex, year of birth and geography of residence. All were followed to 1975, the date of a second census. Mortality rates based on person-years at risk were about the same for widowed as for married females, but significantly higher for male widowed than male married, even after adjustment for a number of demographic, socioeconomic, and behavioral variables. Mortality rates among widowed males who remarried were very much lower than among those who did not remarry, but no significant difference was observable among widowed females who did nor did not remarry. Multiple regression analysis also showed that, for both sexes and independently of other factors, moving into a nursing home or other chronic care facility was associated with higher mortality than any other residential change or no change, and living alone was associated with higher mortality than living with someone else in the household.

Respiratory effects on household exposures to tobacco smoke and gas cooking.

The records of 1,724 residents of Washington County, Maryland, who had participated in 2 studies of respiratory symptoms and ventilatory function were analyzed to evaluate the effects of exposures at home to tobacco smoke generated by other members of their households and to fumes from the use of gas as a cooking fuel. Currently smoking subjects showed the highest frequency of respiratory symptoms and impaired ventilatory function; former smokers showed a lower frequency of these findings; and persons who had never smoked had the lowest prevalence of abnormal respiratory findings. The presence of a smoker in the household other than the subject was not associated with the frequency of respiratory symptoms, and only suggestively associated with evidence of impaired ventilatory function. The use of gas for cooking was related to an increased frequency of respiratory symptoms and impaired ventilatory function among men, being most marked among men who had never smoked. There was not evidence that cooking with gas was harmful to women.

Mortality after bereavement.

A nonconcurrent prospective study in Washington County, Maryland, identified 4032 (1204 male, 2828 female) white persons aged 18 years and over who were enumerated in a 1963 nonofficial census and became widowed between 1963 and 1974, and an equal number of married persons, each matched to a widowed person as to race, sex, year of birth and geography of residence. All were followed to 1975, the date of a second census. Mortality rates based on person-years at risk were virtually no different for female widowed than married, but significantly higher for male widowed than married, even after adjustment for a number of demographic, socioeconomic and behavioral variables. The male widowed in all age groups experienced higher mortality than the male married, the relative risk attaining statistical significance only in age groups 55--64 and 65--74 years, although the indicated relative risk was even higher in the younger age groups. There was little evidence of higher mortality in the first or second six-month intervals following bereavement than in subsequent years for either sex, but a suggestively higher mortality in year 2 for female widowed under age 65 years.