Cynical hostility in adult male twins.

The heritability of hostility as measured by the Cook and Medley Ho scale was assessed in an adult male sample of 60 monozygotic and 61 dizygotic twin pairs. For the total Ho scale, as well as its health predictive component, the results were consistent with a moderate genetic effect. Results are discussed in terms of genetic and environmental influences on the development of this trait, and possible genetic contributions to the association between hostility and subsequent health.

Tobacco, alcohol, coffee, and caffeine as risk factors for colon cancer in a low-risk population.

We used data from a population-based case-control study to examine how use of tobacco products and consumption of alcohol, coffee, and caffeine relate to colon cancer in Utah. We hypothesized that low use of these substances is one factor contributing to the low colon cancer incidence in Utah and could help explain the low risk associated for colon cancer with being a member of the Church of Jesus Christ of Latter-day Saints. In females, we observed little or no increase in risk of colon cancer from smoking cigarettes or from consumption of alcohol, caffeine, or coffee. Males who used pipes, however, experienced an increased risk for colon cancer (OR = 4.1, 95% CI = 1.3-12.3). Risk for colon cancer associated with alcohol use was greatly attenuated after adjusting for caffeine and pipe use in males; males who consumed higher levels of caffeine during the two to three years prior to the interview were at higher risk than males who consumed low levels of caffeine (OR = 2.0, 95% CI = 1.0-4.2); similar associations were observed for coffee consumption. Nonuse of these substances could explain the low colon cancer incidence rates observed in members of the Church of Jesus Christ of Latter-day Saints and Utah males.

Dietary intake and colon cancer: sex- and anatomic site-specific associations.

A case-control study was conducted in Utah between July 1979 and June 1983 in which 231 cases of colon cancer identified through the Utah Cancer Registry and 391 controls identified through random digit dialing were interviewed. Odds ratios (OR) were calculated comparing the highest exposure categories with the lowest exposure categories. The highest quintile of body mass index (weight (kg)/height (m)2 for males; weight (kg)/height (m)1.5 for females) was associated with increased risk in both males (OR = 2.1) and females (OR = 2.3). In females, total dietary fat (OR = 1.9) and energy intake (OR = 1.5) were associated with an increased colon cancer risk after adjusting for age, body mass index, and crude fiber. Fiber was protective in females (OR = 0.5) after adjusting for age, body mass index, and energy intake, as was beta-carotene (OR = 0.5) after also adjusting for crude fiber. Adjusted risk estimates in males were 2.0 for total dietary fat, 3.8 for polyunsaturated fat, 2.1 for monounsaturated fat, 2.1 for energy intake, 2.5 for protein, 0.3 for fiber, 0.4 for beta-carotene, and 0.3 for cruciferous vegetables. Risk estimates differed by site of cancer within the colon. In males, protein (OR = 3.8) was a risk factor for cancer of the descending colon, while fats (OR = 2.7-8.8) increased the risk of cancer of the ascending colon. The hypotheses that dietary fat increases colon cancer risk while dietary fiber decreases colon cancer risk and that fat and protein may be independently associated with colon cancer risk are supported.

Validity of cigarette smoking habits in three epidemiologic studies in Utah.

Utah has lower incidence and mortality for many smoking-related forms of cancer and heart disease. It is an important epidemiologic question to assess whether the population attributable risk associated with cigarette smoking in this low-risk population is biased from under-reporting because of societal pressures not to smoke. To answer this question, we compared reported cigarette use to serum cotinine values in three different epidemiologic study designs. Included in these analyses were data from men interviewed for a cross-sectional study of dietary intake and hormones, women interviewed as a part of a case-control study of cervical cancer, and men interviewed in conjunction with a cardiovascular disease and hypertension family follow-up study. Cross-sectional study participants reported accurate cigarette usage 93.8% of the time; case-control participants accurately reported cigarette use 98.5% of the time; participants interviewed in the family cohort study correctly reported usage 82.8% of the time. Most inaccurate reporting of smoking was by exsmokers being followed for a disease known to be linked to smoking. The low attributable risk of smoking related to diseases in Utah is not from underreporting of cigarette smoking, and makes Utah an ideal population to examine other risk factors for diseases where smoking increases risk.

Relationship between body mass index, cigarette smoking, and plasma sex steroids in normal male twins.

Smoking has been observed to affect plasma sex hormones and body mass index. The relationship between smoking, body mass index, and plasma concentration of sex hormones was studied in normal adult male twins. The analyses were performed for between 150 and 159 twin pairs for whom hormonal data were available on both twins. With bivariate analysis, neither body mass index nor smoking affected estrone, luteinizing hormone, follicle-stimulating hormone, ratio of testosterone to estradiol, or ratio of testosterone to dihydrotestosterone. Body mass index significantly (P less than 0.05) affected sex hormone binding globulin, whereas smoking had no effect. The plasma contents of testosterone and dihydrotestosterone and the luteinizing hormone/testosterone ratio were affected by both body mass index and smoking, although, after allowing for body mass, smoking was less significant (0.05 less than P less than 0.10). A path model was formulated to examine the relationship of body mass and sex steroid levels. Our results suggest that body mass index affects sex steroids, since common environmental factors do not account for the strength of the relationship. The bivariate analysis suggests that the smoking effect on sex hormones (except perhaps for dihydrotestosterone) is secondary to an effect on body mass index.

Dietary calcium intake as a mitigating factor in colon cancer.

A population-based case-control study was conducted in Utah to test the hypothesis that calcium decreases the risk of developing colon cancer. A total of 231 cases and 391 controls were identified and interviewed between 1979 and 1982. A quantitative food frequency instrument was used to ascertain individual dietary intake two years prior to diagnosis for the cases and two years prior to interview for the controls. Calcium, calcium per 1,000 calories, and total dairy product consumption were used as indicators of dietary calcium intake. Categories of dietary intake were determined by the distribution of these variables in the control population. A protective effect was observed for males for intake of calcium (odds ratio (OR) = 0.48), calcium per 1,000 calories (OR = 0.35), and total diary products (OR = 0.49). The magnitude of the protective effect from calcium intake increased after adjusting for intake of calories (OR = 0.41), protein (OR = 0.31), and fat (OR = 0.46). Calcium provided less of a protective effect in females, with the odds ratio for calcium being 0.50, 0.55, and 0.56 after adjusting for calories, protein, and fat, respectively. Risk associated with calories, protein, and fat also increased after adjusting for calcium. Of interest is an odds ratio of 5.30 in males for protein after adjusting for calcium. A biologic mechanism is presented to help explain the role of calcium in the development of colon cancer.

The effect of nutritional factors on sex hormone levels in male twins.

Dietary intake has been hypothesized as being associated with several hormonally related cancers including prostate, breast, ovarian, and endometrial cancer. Because diet may affect hormones directly, it is logical to examine the effects of dietary factors on hormone production and levels. Therefore, a set of 72 male MZ and 83 male DZ twin pairs was ascertained from the Utah birth certificates. A quantitative food frequency questionnaire was administered and blood samples were drawn for hormonal assays. Heritability estimates for hormonal levels were calculated indicating a range from no heritability for sex hormone binding globulin (SHBG), estrone, and testosterone glucuronide to 70% for androstanediol glucuronide and luteinizing hormone. To examine nutritional factors, the difference in hormone and SHBG levels between each MZ twin and his co-twin were correlated with the difference in nutrient intake. Weight and obesity were significantly correlated with plasma testosterone and follicle stimulating hormone. Fat intake showed a significant association with testosterone. Androstanediol glucuronide, a steroid that reflects tissue formation of dihydrotestosterone, was inversely correlated with caloric intake, theobromine and caffeine. Testosterone glucuronide exhibited significant correlations with calories and vitamin A. This study suggests that dietary intake affects plasma sex-steroid levels in men.

Calcium and colon cancer: a review.

The role of dietary calcium as a protective factor in the etiology of colon cancer is reviewed by examining data from ecological and analytical epidemiological studies. Biological evidence that explains the mechanisms whereby calcium intake could alter risk of developing colon cancer is also presented. The data reviewed here in general support the hypothesis that dietary calcium is linked to colon cancer in a protective manner, and that it may be one component in the etiology of colon cancer which alters an individual's risk of developing the disease.

Blood pressure reactivity in adult male twins.

The purpose of the present investigation was to examine possible genetic contributions to cardiovascular reactivity by contrasting patterns of association in 82 monozygotic (MZ) and 88 dizygotic (DZ) adult male twin pairs (age range = 21 to 61 years, M = 35 years). Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded during baseline and during a mental arithmetic task (i.e., serial subtraction). The task produced significant elevations in all three cardiovascular measures (i.e., 10 mmHg SBP, 8 mmHg DBP, and 6 bpm HR, respectively). Levels of SBP and DBP reactivity were significantly correlated in MZ pairs but not in DZ pairs. Statistical tests suggest a heritability estimate of about 50% that was marginally significantly for SBP and DBP changes during the task. There was no indication of a genetic influence on HR reactivity. Resting level and static task period measures of SBP, DBP, and HR demonstrated statistically significant heritability estimates of 60% to 80%.

Myocardial infarction: a five-year follow-up of patients.

Patients with acute myocardial infarction (2,020) admitted to coronary care units (CCU) in Utah were studied for five years. Of these, 1,641 (81.4 percent) survived to leave the hospital. The male to female ratio was 3.5:1. At four months, one year and yearly thereafter from the date of admission to CCU, patients were mailed follow-up questionnaires. Cause of death was obtained from autopsy reports and death certificates. Patients were grouped yearly by the number of cardiac symptoms reported. Of patients discharged whose cases were followed, 925 (61.9 percent) were alive after five years. Reinfarction was the major cause of death in the hospital; however, during follow-up only 36.8 percent of deaths were attributable to myocardial infarction. At follow-up after a year, fewer cardiac symptoms were reported by patients who survived to the fifth year of follow-up than by patients who did not. Women were older and showed a higher death rate during follow-up. Increasing age was found to be a determining factor in long-term mortality after acute myocardial infarction.