Cohort study of thyroid cancer in a San Francisco Bay area population.

Using data from a large health plan, we performed a cohort study of thyroid cancer among 204,964 persons (aged 10--89 at baseline in 1964--1973, 54% female) followed for a median of 20 years. There were 196 incident thyroid cancers (73 in men, 123 in women). Risk was independently and positively related to female gender [relative risk (RR) = 1.56, 95% confidence interval (CI) = 1.12--2.19], Asian race (RR = 2.86, 95% CI = 1.76--4.65), completed college or post-graduate education (RR = 1.76, 95% CI = 1.20--2.59), history of goiter (RR = 3.36, 95% CI = 1.82--6.20), radiation of the neck region (RR = 2.33, 95% CI = 1.28--4.23) and family history of thyroid disease (RR = 2.18, 95% CI = 1.17--4.05). An inverse association was found for black race (RR = 0.55, 95% CI = 0.33--0.91). Cigarette smoking, alcohol consumption, personal history of hyperthyroidism, hypothyroidism, overweight or obesity, weight gain since age 20, height, occupational exposures, reproductive factors, oral contraceptives and hormone use did not show statistically significant relations to thyroid cancer. These results provide further evidence for a role of female gender, radiation, goiter, Asian race, high educational attainment and family history of thyroid disease in the etiology of thyroid cancer.

Association of basal cell skin cancers with other cancers (United States).

BACKGROUND: Persons with basal cell skin cancer (BCSC) have shown increased risk of developing cancer at several other sites. METHODS: We identified 3164 persons with BCSC and 15,730 comparison subjects matched for age, sex, race, residence area and length of membership in a health maintenance organization. RESULTS: In retrospective follow-up for up to 24 years (mean 11.3 years), BCSC patients experienced statistically significant increases in the incidence of all cancer (relative risk [RR] = 1.2, 95% confidence interval [CI] = 1.1-1.4) lung cancer (RR = 1.4, CI = 1.0-1.8) and melanoma (RR = 2.2, CI = 1.6-3.0). Women experienced significantly increased risk for all cancer, lung cancer, melanoma and thyroid cancer, increases of borderline significance in breast cancer, non-Hodgkin's lymphoma and leukemia, and increased pre-existing bladder cancer. Men showed statistically significant increases in all cancer, melanoma, and kidney cancers, and mouth and throat cancers. Multivariate analysis incorporating available risk factor data did not weaken positive associations with BCSC except slightly for melanoma and for bladder cancer in women. Other previously reported associations were not confirmed. CONCLUSION: Periodic skin examinations appear well justified after removal of BCSC to detect new skin cancers including melanoma. Given the relatively weak, unexplained associations of BCSC with internal cancers, the costs vs. benefits of extra efforts to detect the latter still need to be determined.

Differences in calcium metabolism between black and white men and women.

To determine whether environmental factors influence racial differences in calcium metabolism, the authors evaluated the influence of three factors (season, length of sunlight exposure, and diet) on calciotropic hormones, renal calcium excretion, and markers of bone turnover in an ambulatory population aged 25-36 years. Included were 109 black men, 114 white men, 95 black women, and 84 white women. Compared with white subjects, black subjects of both genders showed lower levels of serum 25-hydroxyvitamin D (25-OHD) and higher levels of serum 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. The mean winter levels of 25-OHD were 19 to 29% lower than the summer levels in all groups. The urinary calcium excretion was 26% lower in black men than in white men and was 36% lower in black women than in white women. The parathyroid hormone levels were 29% higher in black women than in white women, but no statistically significant racial differences in parathyroid hormone levels were seen in men. Bone turnover markers (serum osteocalcin, bone-specific alkaline phosphatase, urinary pyridinoline cross-link excretion) did not show consistent racial differences. Racial and gender differences in calcium excretion did not significantly correlate with differences in lifestyle or with levels of the calciotropic hormones. Environmental factors such as diet and sunlight exposure do not appear to influence racial differences in the levels of the calciotropic hormones or renal calcium excretion.

Effect of cigar smoking on the risk of cardiovascular disease, chronic obstructive pulmonary disease, and cancer in men.

BACKGROUND: The sale of cigars in the United States has been increasing for the past six years. Cigar smoking is a known risk factor for certain cancers and for chronic obstructive pulmonary disease (COPD). However, unlike the relation between cigarette smoking and cardiovascular disease, the association between cigar smoking and cardiovascular disease has not been clearly established. METHODS: We performed a cohort study among 17,774 men 30 to 85 years of age at base line (from 1964 through 1973) who were enrolled in the Kaiser Permanente health plan and who reported that they had never smoked cigarettes and did not currently smoke a pipe. Those who smoked cigars (1546 men) and those who did not (16,228) were followed from 1971 through the end of 1995 for a first hospitalization for or death from a major cardiovascular disease or COPD, and through the end of 1996 for a diagnosis of cancer. RESULTS: In multivariate analysis, cigar smokers, as compared with nonsmokers, were at higher risk for coronary heart disease (relative risk, 1.27; 95 percent confidence interval, 1.12 to 1.45), COPD (relative risk, 1.45; 95 percent confidence interval, 1.10 to 1.91), and cancers of the upper aerodigestive tract (relative risk, 2.02; 95 percent confidence interval, 1.01 to 4.06) and lung (relative risk, 2.14; 95 percent confidence interval, 1.12 to 4.11), with evidence of dose-response effects. There appeared to be a synergistic relation between cigar smoking and alcohol consumption with respect to the risk of oropharyngeal cancers and cancers of the upper aerodigestive tract. CONCLUSIONS: Independently of other risk factors, regular cigar smoking can increase the risk of coronary heart disease, COPD, and cancers of the upper aerodigestive tract and lung.

Marijuana use and medically attended injury events.

STUDY OBJECTIVE: This study evaluated the relation between self-reported marijuana use and 3-year incidence of injury. METHODS: We conducted a retrospective cohort study of adult Kaiser Permanente Medical Care Program members who underwent multiphasic health examinations between 1979 and 1986 (n=4,462). Injury-related outpatient visits, hospitalizations, and fatalities within 3 years of examination were determined. RESULTS: Outpatient injury events totaled 2,524; 1,611 participants (36%) had at least 1 injury-related outpatient visit. Injury-related hospitalizations (n=22) and fatalities (n=3) were rare. Among men, there was no consistent relation between marijuana use and injury incidence for either former users (rate ratio, 1.15; 95% confidence interval [CI], .97 to 1.36) or current users (rate ratio, 0.97; 95% CI, .81 to 1.17), compared with those who had never used marijuana. Among women, former and current users showed little difference in their rate of later injury compared with never users; the rate ratios were 1.05 (95% CI, .87 to 1.26) and 1.20 (95% CI, 1.00 to 1.44), respectively. No statistically significant associations were noted between marijuana use and cause-specific injury incidence in men or women. CONCLUSION: Among members of a health maintenance organization, self-reported marijuana use in adult men or women was not associated with outpatient injury within 3 years of marijuana use ascertainment.

Marijuana use and cancer incidence (California, United States).

The purpose of this retrospective cohort study was to examine the relationship of marijuana use to cancer incidence. The study population consisted of 64,855 examinees in the Kaiser Permanente multiphasic health checkup in San Francisco and Oakland (California, United States), between 1979-85, aged 15 to 49 years, who completed self-administered questionnaires about smoking habits, including marijuana use. Follow-up for cancer incidence was conducted through 1993 (mean length 8.6 years). Compared with nonusers/experimenters (lifetime use of less than seven times), ever- and current use of marijuana were not associated with increased risk of cancer of all sites (relative risk [RR] = 0.9, 95 percent confidence interval [CI] = 0.7-12 for ever-use in men; RR = 1.0, CI = 0.8-1.1 in women) in analyses adjusted for sociodemographic factors, cigarette smoking, and alcohol use. Marijuana use also was not associated with tobacco-related cancers or with cancer of the following sites: colorectal, lung, melanoma, prostate, breast, cervix. Among nonsmokers of tobacco cigarettes, ever having used marijuana was associated with increased risk of prostate cancer (RR = 3.1, CI = 1.0-9.5) and nearly significantly increased risk of cervical cancer (RR = 1.4, CI = 1.0-2.1). We conclude that, in this relatively young study cohort, marijuana use and cancer were not associated in overall analyses, but that associations in nonsmokers of tobacco cigarettes suggested that marijuana use might affect certain site-specific cancer risks.

Marijuana use and mortality.

OBJECTIVES: The purpose of this study was to examine the relationship of marijuana use to mortality. METHODS: The study population comprised 65171 Kaiser Permanente Medical Care Program enrollees, aged 15 through 49 years, who completed questionnaires about smoking habits, including marijuana use, between 1979 and 1985. Mortality follow-up was conducted through 1991. RESULTS: Compared with nonuse or experimentation (lifetime use six or fewer times), current marijuana use was not associated with a significantly increased risk of non-acquired immunodeficiency syndrome (AIDS) mortality in men (relative risk [RR] = 1.12, 95% confidence interval [CI] = 0.89, 1.39) or of total mortality in women (RR = 1.09, 95% CI = 0.80, 1.48). Current marijuana use was associated with increased risk of AIDS mortality in men (RR = 1.90, 95% CI = 1.33, 2.73), an association that probably was not causal but most likely represented uncontrolled confounding by male homosexual behavior. This interpretation was supported by the lack of association of marijuana use with AIDS mortality in men from a Kaiser Permanente AIDS database. Relative risks for ever use of marijuana were similar. CONCLUSIONS: Marijuana use in a prepaid health care-based study cohort had little effect on non-AIDS mortality in men and on total mortality in women.

Racial differences in bone density between young adult black and white subjects persist after adjustment for anthropometric, lifestyle, and biochemical differences.

This study tested whether racial differences in bone density can be explained by differences in bone metabolism and lifestyle. A cohort of 402 black and white men and women, ages 25-36 yr, was studied at the Kaiser Permanente Medical Care Program in Northern California, a prepaid health plan. Body composition (fat, lean, and bone mineral density) was measured using a Hologic-2000 dual-energy x-ray densitometer. Muscle strength, blood and urine chemistry values related to calcium metabolism, bone turnover, growth factors, and level of sex and adrenal hormones were also measured. Medical history, physical activity, and lifestyle were assessed. Statistical analyses using t- and chi-square tests and multiple regression were done to determine whether racial difference in bone density remained after adjustment for covariates. Bone density at all skeletal sites was statistically significantly greater in black than in white subjects; on average, adjustment for covariates reduced the percentage density differences by 42% for men and 34% for women. Adjusted bone density at various skeletal sites was 4.5-16.1% higher for black than for white men and was 1.2-7.3% higher for black than for white women. We concluded that racial differences in bone mineral density are not accounted for by clinical or biochemical variables measured in early adulthood.

Cardiovascular risk factors among Asian Americans.

MANY ASIANS HAVE RECENTLY IMMIGRATED to the United States, but there have been few studies of cardiovascular risk factors in these groups. Researchers analyzed data from 13,031 people who described themselves as Chinese, Filipino, Japanese, and other Asians, and used regression analyses controlled for age, alcohol use, education, and marital status. Adjusted mean body mass index and smoking prevalence were lowest in Chinese men and women. Adjusted total cholesterol levels were highest in Japanese men and women. Hypertension prevalence was highest in Filipino men and women. Comparisons of Asians born outside the United States with those U.S.-born showed 1) no major cholesterol differences; 2) higher body mass index in U.S.-born men, but not in women of most races; 3) more hypertension only in U.S.-born Chinese men; and 4) a lower smoking prevalence in U.S.-born men but generally higher smoking prevalence in U.S.-born women. These data show important ethnic differences in cardiovascular risk factors among Asian Americans and have implications for targeting public health efforts.

A comparison of fecal occult-blood tests for colorectal-cancer screening.

BACKGROUND: Hemoccult II, a widely used guaiac test for fecal occult blood, has a low sensitivity for detecting colorectal neoplasms in asymptomatic patients at average risk. In such patients, the performance characteristics of screening tests developed to improve on Hemoccult II are not known. METHODS: A set of three fecal occult-blood tests--Hemoccult II; Hemoccult II Sensa, a more sensitive guaiac test; and HemeSelect, an immunochemical test for human hemoglobin--was mailed to all patients 50 years of age or older who were scheduled for personal health appraisals at the Kaiser Permanente Medical Center in Oakland, California. The performance of each test and of a combination test (HemeSelect to confirm positive Hemoccult II Sensa results) was evaluated by identifying screened patients who had colorectal neoplasma (carcinoma or a polyp > or = 1 cm in diameter) in the two years after screening. RESULTS: Of the 10,702 eligible patients, 8104 (75.7 percent) had at least one interpretable sample and were screened on the basis of at least one test; 96 percent of these patients had complete two-year follow-up. The sensitivity of the tests for detecting carcinoma was lowest with Hemoccult II (37.1 percent; 95 percent confidence interval, 19.7 to 54.6 percent), intermediate with the combination test (65.6 percent; 95 percent confidence interval, 47.6 to 83.6 percent) and with HemeSelect (68.8 percent; 95 percent confidence interval, 51.1 to 86.4 percent), and highest with Hemoccult II Sensa (79.4 percent; 95 percent confidence interval, 64.3 to 94.5 percent). The specificity for detecting carcinoma was 86.7 percent with Hemoccult II Sensa, 94.4 percent with HemeSelect, 97.3 percent with the combination test, and 97.7 percent with Hemoccult II. HemeSelect and the combination test detected more colorectal carcinomas and polyps than Hemoccult II, with only slight increases in the number of colonoscopies needed. CONCLUSIONS: HemeSelect and a combination test in which HemeSelect is used to confirm positive Hemoccult II Sensa results improve on Hemoccult II in screening patients for colorectal carcinoma.

Mentholated cigarette use and lung cancer.

BACKGROUND: Menthol combustion produces carcinogenic compounds such as benzo[a]pyrenes. Mentholated cigarettes are much more commonly smoked by black individuals than by white individuals. The incidence of lung cancer is much higher (60%) in black men than in white men, but it differs little by race in women. We examined the association of mentholated cigarette use with lung cancer in men and women because mentholated cigarette use could help to explain the higher incidence rate of lung cancer in black men than in white men. METHODS: The study population consisted of 11,761 members of the Northern California Kaiser Permanente Medical Care Program, Oakland (5771 men and 3990 women), aged 30 to 89 years, who underwent a multiphasic health checkup in 1979 through 1985 and reported that they were current cigarette smokers who had smoked for at least 20 years. Data were collected about current cigarette brand, duration of mentholated cigarette use, and other smoking characteristics. Follow-up for incident lung cancer cases (n = 318) was carried out through 1991. RESULTS: The relative risk of lung cancer associated with mentholation compared with nonmentholated cigarettes was 1.45 in men (95% confidence interval, 1.03 to 2.02) and it was 0.75 in women (95% confidence interval, 0.51 to 1.11), adjusted for age, race, education, number of cigarettes smoked per day, and duration of smoking. Further adjustment for tar content and self-reported smoking intensity characteristics did not substantially alter the estimate of relative risk. A graded increase in risk of lung cancer with increasing duration of mentholated cigarette use was present in men. CONCLUSION: This study suggests that there is an increased risk of lung cancer associated with mentholated cigarette use in male smokers but not in female smokers.

The effect of retirement on mental health and health behaviors: the Kaiser Permanente Retirement Study.

To assess the short-term effect of retirement on mental health and health behaviors of members of a health maintenance organization aged 60-66, questionnaires were completed in 1985 and 1987 by employed members planning to retire during the study period and those not planning to retire. Mental health and health behaviors of members who actually retired (n = 320) were compared with those members who did not retire (n = 275). Using logistic regression controlling for age, gender, marital status, and education, we found that retired members were more likely to have lower stress levels and to engage in regular exercise more often as compared to those who did not retire during the study period. Retired women were more likely to report no alcohol problems as compared to nonretired women. There were no differences between the groups on self-reported mental health status, coping, depression, smoking, alcohol consumption, and frequency of drunkenness. These findings underscore the importance of assessing positive benefits associated with retirement and call for further evaluation of whether these benefits persist over time.

Iron stores are not associated with acute myocardial infarction.

BACKGROUND: This study evaluated the relation between body iron stores and coronary artery disease. It has been suggested that total body iron stores are an independent risk factor for acute myocardial infarction (AMI). METHODS AND RESULTS: Our study population consisted of 46,932 members of a prepaid health plan who were > or = 30 years old and who received a standard health check between 1969 and 1971. Blood collected during this examination was analyzed for serum iron and total iron-binding capacity. Transferrin saturation (TS), calculated as (serum iron/total iron-binding capacity) x 100, was categorized as low (< or = 10%), normal (11% to 61%), or elevated (> or = 62%). Hospital stays for AMI were identified from the health plan's computerized discharge records for its Northern California Region through December 31, 1991. Mean follow-up time was 14.1 years. During the follow-up period, 969 men and 871 women had an AMI-related hospital stay. Analysis of AMI-related hospital stays was performed overall and by sex. Age-adjusted incidence rates were obtained for each TS level, and proportional hazards regression models were used to assess the significance of TS as a risk factor for AMI, controlling for other known coronary disease risk factors. Our results did not show iron deficiency as defined by low TS to be protective against AMI. Subjects with increased iron stores indicated by TS > or = 62% had a relative risk for AMI of 1.3, which was not statistically significant. CONCLUSIONS: Our observations do not support the hypothesis that coronary artery disease risk is related to iron stores.

Health care use by frequent marijuana smokers who do not smoke tobacco.

Even though marijuana smoke contains carcinogens and more tar than tobacco smoke and marijuana intoxication has been implicated as a risk factor for injuries, relatively little epidemiologic evidence has identified marijuana use as a risk factor for ill health. This study is the first to examine the health effects of smoking marijuana by comparing the medical experience of "daily" marijuana smokers who never smoked tobacco (n = 452) with a demographically similar group of nonsmokers of either substance (n = 450). Marijuana smoking status was determined during multiphasic health checkups at Kaiser Permanente medical centers between July 1979 and December 1985. Medical records were reviewed for as long as 2 years after the checkups. Frequent marijuana smokers had small increased risks of outpatient visits for respiratory illnesses (relative risk [RR] = 1.19; 95% confidence interval [CI] = 1.01, 1.41), injuries (RR = 1.32; CI = 1.10, 1.57), and other types of illnesses (RR = 1.09; CI = 1.02, 1.16) compared with nonsmokers; their risk of being admitted to a hospital was elevated but not statistically significant (RR = 1.51; CI = 0.93, 2.46). Analyses were adjusted for sex, age, race, education, marital status, and alcohol consumption. Daily marijuana smoking, even in the absence of tobacco, appeared to be associated with an elevated risk of health care use for various health problems.

A prospective study of cigarette tar yield and lung cancer.

We examined the relationship of cigarette tar yield and other cigarette-usage characteristics in current smokers to the incidence of lung cancer in a study population of 79,946 Kaiser Permanente Medical Care Program members, aged 30-89 years, who completed a detailed, self-administered, smoking-habit questionnaire during the years 1979 through 1985. Mean length of follow-up was 5.6 years. There were 302 incident lung cancers, of which 89 percent occurred in current or former smokers. The tar yield of the current cigarette brand was unassociated with lung cancer incidence (relative risk [RR] = 1.02 per 1 mg tar-yield in men, 95 percent confidence interval [CI] = 0.98-1.05; RR = 0.99, CI = 0.96-1.03 in women). However, in long-term (> 20 years) smokers, the risk of lung cancer was decreased in women who had smoked filtered cigarettes for 20 or more years relative to lifelong smokers of unfiltered cigarettes (RR = 0.36, CI = 0.18-0.75), but not in men who had smoked filtered cigarettes for 20 or more years (RR = 1.04, CI = 0.58-1.87).

Home blood pressure monitoring. Effect on use of medical services and medical care costs.

The objective of this study was to determine whether a hypertension management program in which patients monitor their own blood pressure (BP) at home can reduce costs without compromising BP control. The prospective, randomized, controlled 1-year clinical trial was conducted at four medical centers of the Kaiser Permanente Medical Care Program in the San Francisco Bay Area. Of 467 patients with uncomplicated hypertension who were referred by their physicians, 37 declined to participate in the study; 215 were randomly assigned to a Usual Care (UC) group and 215 to a Home BP group. Twenty-five UC patients and 15 Home BP patients did not return for year-end BP measurements. Patients in the UC group were referred back to their physicians. Patients in the Home BP group were trained to measure their own BP and return the readings by mail. Patients were given a standard procedure to follow in case of unusually high or low BP readings at home. The number and type of outpatient medical services used were obtained from patient medical records for the study year and the prior year. Costs of care for hypertension were calculated by assigning relative value units to each outpatient service. Trained technicians measured each patient's BP at entry into the study and 1 year later. Home BP patients made 1.2 fewer hypertension-related office visits than UC patients during the study year (95% confidence interval (CI): 0.8, 1.7). Mean adjusted cost for physician visits, telephone calls, and laboratory tests associated with hypertension care was $88.76 per patient per year in the Home BP group, 29% less than in the UC group (95% CI: $16.11, $54.74). The annualized cost of implementing the home BP system was approximately $28 per patient during the study year and would currently be approximately $15. After 1 year, BP control in men in the Home BP group was better than in men in the UC group; BP control was equally good in women in both groups. Management of uncomplicated hypertension based on periodic home BP reports can achieve BP control with fewer physician visits, resulting in substantial cost savings.

Hemoccult screening in detecting colorectal neoplasm: sensitivity, specificity, and predictive value. Long-term follow-up in a large group practice setting.

STUDY OBJECTIVE: To determine the sensitivity, specificity, and predictive value of Hemoccult II tests for detecting colorectal neoplasm (colorectal carcinoma or polyp or both). STUDY DESIGN: Prospective analyses of asymptomatic patients (greater than or equal to 45 years) followed for 4 years after screening with Hemoccult II testing and retrospective analyses of patients, with known colorectal carcinoma or polyps or both who had Hemoccult II testing within 2 years of diagnosis. SETTING: A large, health maintenance organization practice. MEASUREMENTS AND MAIN RESULTS: In the prospective analysis, the sensitivity of Hemoccult II was 50% for colorectal carcinoma diagnosed within 1 year of testing, 43% within 2 years, and 25% within 4 years. For polyps, sensitivity was 36% at 1 year, 28% at 2 years, and 17% at 4 years. Specificity was 99%. The predictive value of a positive test for colorectal carcinoma was 8% at 1 year, 10% at 2 years, and 11% at 4 years. On the basis of the retrospective analyses, the sensitivity of Hemoccult II for colorectal carcinoma diagnosed within 1 year of testing was 66% and was 61% within 2 years. Many of these patients had symptoms when tested. CONCLUSIONS: An asymptomatic patient age 45 or older with a positive Hemoccult II test has about a chance of 1 in 10 for having colorectal carcinoma and a 1-in-3 chance of having either a colorectal carcinoma or polyp: The same patient with a negative Hemoccult test has a 0.2% chance of having a colorectal carcinoma diagnosed within 2 years of testing and a 0.7% chance of having a polyp. Within 4 years of testing the chance increases to 0.5% for colorectal carcinoma and 1.5% for polyps. If Hemoccult II slides are the only screening method used for detecting asymptomatic colorectal neoplasms, 50% to 60% of lesions will remain undetected. Clinical interpretation of Hemoccult screening requires appreciation of its limits as well as its benefits.