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Survival analysis techniques were used in estimating lifetime inpatient utilization among patients diagnosed with acquired immunodeficiency syndrome (AIDS) using data on 863 members of the Kaiser Permanente Medical Care Program in the Northern California Region diagnosed with AIDS between January 1, 1981 and June 30, 1987. Using information on both deceased and living patients, we estimated means of 40.3 lifetime inpatient days and 3.3 hospitalizations among all AIDS patients. Those presenting with Kaposi's sarcoma experienced a mean of 7.6 fewer lifetime inpatient days than those presenting with Pneumocystis carinii pneumonia (95% confidence interval = .61, 14.6) and a mean of 11.0 (3.9, 18.6) fewer inpatient days than all other AIDS patients. Older patients had fewer hospital admissions than younger ones. Year of diagnosis does not appear to be related to lifetime utilization, and there is an indication that increased survival has been accompanied by decreased inpatient utilization intensity as measured on a per person-year basis. We recommend the use of survival analysis methods in the study of utilization among groups of patients with incomplete follow-up.

The epidemiology of inflammatory bowel disease is described among the more than 1.5 million members of the Kaiser Permanente Medical Care Program (KPMCP) in northern California. We reviewed a 20% random sample of the medical records of 2,067 persons first admitted to hospital in the period 1971 through 1982 with codes indicating inflammatory bowel disease. We also examined all new outpatient cases for a 1-year period from records at the Oakland KPMCP facility. Criteria used to establish valid cases adhered to standards used in previous studies but were revised to reflect current diagnostic methods. The disadvantages of using hospital discharge data have been identified and quantified. In this population, only 21% of ambulatory patients with inflammatory bowel disease were admitted to hospital in a 3 1/2-year period. There was no difference in the incidence of the disorder by sex or between whites and blacks, but it was rare in Asians. A bimodal age distribution was suggested for Crohn's disease but not for ulcerative colitis. During the 12 years of this study, rates of hospital admissions for ulcerative colitis decreased and for Crohn's disease were slightly increased.

Recent studies have suggested a role for dietary fat in the etiology of breast cancer. The relation of serum cholesterol and other serum lipid measures to breast cancer incidence was investigated in a cohort of 95, 179 women who had multiphasic health checkups from 1964 through 1972. Through 1977, 1,035 new breast cancer cases occurred in over 752,000 person-years of follow-up. Age-adjusted incidence rates were 1.45, 1.37, 1.31, and 1.40/1,000 person-years from the lowest to the highest quartile of serum cholesterol level, respectively. Similarly, no statistically significant relation was detected between beta-lipoprotein or total lipids and breast cancer. The sample size was sufficiently large to have detected a relative risk of 1.4 or larger with a probability of 99.9% at the 0.05 level of significance. The expected relation od breast cancer to established risk factors was confirmed by univariate analysis, and serum cholesterol and breast cancer were not associated after simultaneous consideration of nine other risk factors by multivariate analysis. These data suggest that the postulated causal relation between dietary fat and breast cancer does not act via an effect on circulating lipid levels.

The Boqueron Schistosomiasis Project is a prospective community-based study of Schistosoma mansoni infection after the interruption of transmission by nonchemotherapeutic control measures. The study methods and the parasitologic results of the first five annual stool surveys are described in this report. In the first year, 1972, among 904 inhabitants (88% of the total population) the prevalence of infection was 40%, and the geometric mean intensity of infection among positives was 16.1 eggs per gram (epg). Snail control was begun in early 1973 with molluscicides and habitat modification. Intensive monitoring every 2 weeks revealed only 63 noninfected Biomphalaria glabrata in the community during the subsequent 4 years. The incidence of new infectins among people negative in all previous surveys dropped from 17% in 1972 to 1% in 1974 and has remained negligible since then. Among young children and newborn, only four new infections (all less than 5 epg) were found after the first control year. Despite this low rate of transmission, prevalence only decreased from 37% to 34%, and the population geometric mean fecal egg output has not substantially changed in a cohort of 528 individuals examined in each of the six annual surveys. Possible reasons for the minimal change in parasitologic status are discussed and include water contact behavior outside the community and changes in laboratory techniques. Data from the first 5 years of the study suggest that in a population where mean intensity of infection with S. mansoni is low, further decreases in prevalence and intensity of infection occur slowly. The implications for control programs based on nonchemotherapeutic measures are discussed.

The efficacy of the Haemophilus influenzae type b (Hib) polyribose phosphate vaccine was evaluated in a population of 120,000 children from 23 through 71 months of age in the Kaiser Permanente Medical Care Program (KPMCP) in Northern California over the 2-year period from June 1, 1985, through May 31, 1987. Approximately 37% of the population were vaccinated by the end of the first year and 60% were vaccinated by the end of the second year. There were 35 cases of Hib disease, 4 of whom were vaccine failures. Cases of Hib disease were identified by multiple modality case ascertainment, consisting of: (1) active surveillance in KPMCP microbiology laboratories; (2) active surveillance on KPMCP pediatric wards by a study physician; (3) retrospective review of computer-stored hospital discharge diagnoses; and (4) a review of all hospitalizations outside the health plan. The medical records of cases, matched controls and a random sample of the population were reviewed to obtain information on vaccination and related variables. Efficacy was evaluated using two complementary methods. In a retrospective surveillance approach, efficacy was estimated to be 68% (95% confidence limits of 4, 89%). In a matched case-control analysis, efficacy was estimated to be 69% (95% confidence limits of -13, 91%). Adjustment for day care attendance and parental occupation slightly reduced the efficacy estimate. Other possible confounders including race, parental education and number of siblings were considered. Four cases of Hib disease were observed within 1 week following receipt of vaccine and before the time when immunity could have developed. There are several plausible explanations for the occurrence of these early cases including the possibility of chance alone.(ABSTRACT TRUNCATED AT 250 WORDS)

To define further the role of circulating immune complexes in acute schistosomiasis, serial determinations of [125I]Clq binding activity (ClqBA) in 15 patients with this disease were made before and after treatment with niridazole. Levels of ClqBA were elevated in 13 of these patients and in general rose early in the course of disease, reaching maximal levels by 10 weeks after exposure; the levels were correlated with disease severity (r = 0.70, P less than 0.01) and with the concentration of Schistosoma mansoni eggs in the stool (r = 0.59, P less than 0.05). The rise and fall in levels of ClqBA was associated in most instances with the temporal course of other laboratory values reflecting disease activity. The close association of circulating immune complexes with measures of disease activity suggests that these complexes are important in the pathogenesis of acute schistosomiasis.

Use of visual display terminals (VDTs) was examined in a case-control study of pregnancy outcome among 1,583 pregnant women who attended three Kaiser Permanente obstetrics and gynecology clinics in Northern California, 1981-1982. We found a significantly elevated risk of miscarriage for working women who reported using VDTs for more than 20 hr per week during the first trimester of pregnancy compared to other working women who reported not using VDTs (odds ratio 1.8, 95% CI: 1.2-2.8). This risk could not be explained by age, education, occupation, smoking, alcohol consumption, or other maternal characteristics. No significantly elevated risk for birth defects was found among working women although odds ratios were 1.4 for both moderate and high VDT exposure, compared with no exposure (95% CI: 0.7-2.7 and 0.7-2.9, respectively). One possible explanation for these findings is that women who had adverse pregnancy outcomes may have overreported their exposures to VDTs and/or women with normal births may have underreported theirs. The findings may also be due to unmeasured factors confounded with high VDT use such as poor ergonomic conditions or job-related stress. That VDTs themselves are hazardous to the pregnant operator remains a possibility. Our results underscore the need for large cohort studies of working women that will provide objective measures of VDT exposures, ergonomic factors, and stress.

A population-based approach was used to investigate morbidity from Schistosoma mansoni in a rural community in eastern Puerto Rico that was representative of remaining endemic foci on the island. In 1974 the prevalence of infection 855 of 1,056 inhabitants was 32.7% and the geometric mean egg output was 17.6 eggs per gram. A standardized medical history was obtained, and physical and laboratory examinations were performed on 737 (70%) of the community residents. Quantitative S. mansoni egg counts were performed on 1 gram of feces with a modified Ritchie formol-ether concentration technique; other intestinal parasites were recorded on a semi-quantitative basis. Interviews and physical examinations were conducted "blind" to minimize observer bias, and statistical analysis was done on data from 149 infected subjects and 149 noninfected controls matched by age and sex. For subjects under 20 years of age the frequency of hookworm infection and trichuriasis and absolute eosinophilia was significantly higher in the infected group, but no difference was found in the frequency of signs and symptoms of schistosomiasis. For the subjects 20 years and over, the symptom "blood in the stool" was reported more frequently in the infected group, but hematocrit level did not differ between infected and noninfected controls. Although palpable livers were noted more frequently in infected (8) than in noninfected (1) subjects 20 years and over, further evaluation of these subjects cast doubt upon a causal role for S. mansoni. These data indicate that morbidity from S. mansoni infection in the community is low, a finding consistent with the apparent decline in S. mansoni morbidity in Puerto Rico during recent decades and the relatively low intensity of infection in this community. Nevertheless, because of the sporadic occurrence of S. mansoni-induced disease on the island, and because heavily infected subjects are clearly at greater risk of disease, we are recommending treatment for community residents with high egg output.

We examined breast cancer incidence in a cohort of about 69,000 women who answered detailed questions about alcohol consumption from 1979 to 1984. Among women with no prior cancer, breast cancer had developed in 303 by the end of 1984 for an age-adjusted incidence of 1.3/1,000 person years of follow-up. In analysis controlling only for age there was a progressive increase in breast cancer incidence corresponding to each higher level of reported alcohol consumption. In multivariate analyses controlling for age, race, body mass, and smoking, the relative risk at 1-2 drinks/day was 1.5 (95% confidence interval (CI) 1.0-2.3), at 3-5 drinks/day was 1.5 (95% CI 0.8-2.8), and at 6 or more drinks/day was 3.3 (95% CI 1.2-9.3). Past drinkers tended to have been heavier drinkers than current drinkers and had a relative risk of 2.2 (95% CI 1.2-3.9). Study of wine, beer, and liquor use did not suggest that any particular alcoholic beverage was responsible. Significant associations with heavy alcohol consumption were strongest among white and postmenopausal women. This study adds support to the growing evidence that alcohol may be a risk factor for development of breast cancer.

Using laboratory tests and the presence of complaints thought to be associated with hyperparathyroidism, we retrospectively studied 160 patients found to have hypercalcemia on a routine multiphasic examination in two different calendar years. Each case was compared to a matched control, and mean follow-up was 8.5 yr. The diagnosis of presumptive hyperparathyroidism was made by attempting to eliminate any confounding causes of hypercalcemia and by performing parathyroid hormone assays in 41 unoperated patients. Fifteen patients had a parathyroid adenoma removed (12 during and 3 after the duration of the study). Except for an increase in the incidence of hypertension in black male patients, we noted no significant differences in symptomatology or renal function between patients and matched controls. We conclude that most patients with mild persistent (presumptive) hyperparathyroidism may be left untreated under surveillance for long periods of time without the development of significant complications.

The rate of occurrence of stones of the urinary tract was assessed in a large population served by the Northern California Kaiser Foundation Health Plan. The study involved three separate groups. First, data were obtained by questionnaire from approximately 175,000 adults who took a multiphasic health checkup in the period 1964-1972; of these generally well adult members, 26.2/1000 persons (32.0/1000 men and 21.0/1000 women) reported having ever been told by a physician that they had a urinary tract stone. Second, data were obtained from 139,000 persons served by the San Francisco outpatient facility in 1970-1972; 1.22/1000 per year (1.81/1000 men and 0.59/1000 women) had an initial diagnosis of a "new or recurrent" stone of the upper urinary tract. The third set of data was procured from the entire Northern California region in 1971-1975; 0.36/1000 (0.52/1000 men and 0.19/1000 women) were discharged from a hospital each year with a diagnosis of upper urinary tract stone. All rates were age-adjusted to the 1960 US Census population. Of these three rates, the rate derived from the outpatient visit record most closely estimates incidence, since nearly all persons who are hospitalized are first seen as outpatients. Rates of kidney stone diagnosis were three times more common in men and, although rare before 20 years of age, the frequency increased rapidly and peaked in the age group 40 to 59 years. Rates were approximately twice as high in whites as in blacks and Orientals; the frequency of stones was inversely related to socioeconomic status as measured by level of education. Over 90% of stones occurred in the upper urinary tract, and the majority contained calcium oxalate. Population-based rates of occurrence of kidney stones are not generally available in the United States. Comparisons with the few available studies indicate that rates in the Kaiser Foundation Health Plan population may be high.

The intradermal reaction with Schistosoma mansoni adult-worm antigen (35-40 microgram/ml nitrogen) was evaluated as an edpidemiologic tool in an endemic Puerto Rican community where the prevalence of S. mansoni infection was 36% and the geometric-mean egg count was 17.6 eggs/g. Subcutaneous injections of antigen were made in forearms, and stool specimens were examined for S. mansoni eggs by a formol-ether concentration method. Of 296 persons tested, 43% had positive intradermal reactions (greater than or equal to 1.0 cm 2 at least twice the area of the control wheal), compared to 48% positive stool examinations. However, sensitivity was low at 36% for children 14 yr old or less, and only 73% to 79% for adults. The test results were very specific for children (96%), but 32% of stool negative adults were positive. Mean wheal area was not directly related to intensity of infection as determined by egg counts in either children or adults, but did increase directly with age. Mean wheal areas were greater for males than females (both children and adults) at all intensities of infection. Because of unsatisfactory sensitivity and specificity the intradermal test may overestimate the prevalence of infection when rates are low, and underestimate prevalence of infection when rates are high. For its proper interpretation, complementary parasitologic data from stool surveys are required.