A case-control study of breast cancer and hormonal contraception in Costa Rica.

By 1981, 11% of married women in Costa Rica ages 20-49 years had used depot-medroxyprogesterone acetate (DMPA) and 58% had used oral contraceptives (OCs). Since 1977, the Costa Rican Ministry of Health has maintained a nationwide cancer registry. These circumstances provided an opportunity for a population-based, case-control study of DMPA, OCs, and breast cancer in Costa Rica. Cases were 171 women ages 25-58 years with breast cancer diagnosed between 1982 and 1984; controls were 826 women randomly chosen during a nationwide household survey. Cases and controls were interviewed with the use of a standard questionnaire covering their reproductive and contraceptive histories. Logistic regression methods were used to adjust for confounding factors. While few cases or controls had ever used DMPA, DMPA users had an elevated relative risk (RR) estimate of breast cancer of 2.6 (95% confidence limits = 1.4-4.7) compared with never users. However, no dose-response relationship was found; even the group of women who had used DMPA for less than 1 year had an elevated RR estimate (RR = 2.3; 95% confidence limits = 1.0-5.1). In contrast, OC users had no elevation in RR compared with never users (RR = 1.2; 95% confidence limits = 0.8-1.8). The results of the DMPA analysis are inconclusive. Before decisions are made on whether to continue providing this effective contraceptive method, other ongoing studies will need to confirm of refute these findings.

PIP: Depot-medroxyprogesterone acetate (DMPA) is used by approximately 2 million women world-wide. In Costa Rica, by 1981 11% of the married women had used DMPA. Although no definitive link between the use of DMPA and the development of cancer has been found, the possibility has been recognized as one of the reasons for the U.S food and Drug Administration denying approval of the drug. Since 1977, the Ministry of Health in Costa Rica has sustained a national cancer registry. The accuracy of the reporting of the registry was studied by comparing a sampling of gynecologic cancer cases in the year 1983 to the national registry. In examination of the records, an elevated relative risk of breast cancer for DMPA users was found (2.6), and an elevated relative risk for women who had even used DMPA for a short period of time (2.3). The failure to interview 1/3 of the cases, differences in detection and the misclassification of DMPA use contributed cumulatively to the belief that a positive connection between breast cancer and DMPA use could otherwise be drawn. In contrast to the association found between DMPA ever use and breast cancer, no connection was found between OC use and the incidence of breast cancer. However, due to the small number of DMPA users recorded and the void of complete and accurate recorded information, the study results remain inconclusive.

Abortions that fail.

In this study of 33,090 suction curettage abortions performed at less than or equal to 12 weeks' gestation, the rate of unrecognized failed abortions was 2.3 per 1000 abortions. Women with one or more prior pregnancies and those having an abortion at less than or equal to six weeks' gestation, particularly when small suction cannulae were used, were at higher risk for this complication (relative risks of 2.2, 2.9, and 11.1, respectively). Failures were also more likely when abortions were performed by resident physicians (relative risk of 2.2) and when they were performed on women with uterine anomalies (relative risk of 90.6). Physicians can minimize the risk of failed abortion by selecting an appropriate suction cannula size and by planning the optimal time to perform the abortion. Likewise, abortions performed either by residents or on women with uterine anomalies merit extra care.

Comparison of endometrial biopsy with the endometrial Pipelle and Vabra aspirator.

Endometrial biopsy can be used to evaluate women at high risk for endometrial cancer and to follow women on hormone replacement therapy. Biopsy methods may produce enough pain, however, to lower patient acceptance. The Endometrial Pipelle is a new plastic endometrial suction curette that provides a histologic biopsy. This study compared the performance of the Pipelle to that of the Vabra aspirator, a widely accepted biopsy device. Endometrial sampling using both techniques was performed on 56 patients. Both instruments provided the correct diagnosis in 50 patients (89%). The Pipelle obtained more tissue than the Vabra in 28 patients (50%) and was noted by the clinician to cause less pain in 50 patients (89%). Forty-seven patients (84%) stated that biopsy with the Pipelle was less painful than with the Vabra. These results suggest that the Pipelle is as efficacious as the Vabra aspirator and has greater patient acceptability.

Current epidemiology of pertussis in the United States.

The incidence of pertussis in the United States decreased rapidly during the 20th century, with the most impressive decreases resulting from the widespread use of DTP vaccine since the late 1940's. As a result of immunization laws, vaccine coverage levels against pertussis at school entry have been greater than 95% since 1980. National surveillance for pertussis done by the Centers for Disease Control (CDC) consists of two parts: a weekly telephone reporting system and a written case report system providing more detailed demographic, clinical, and laboratory information. In addition, data on secondary spread of pertussis among household contacts of reported cases were available on a small proportion of reported cases during 1979-1983. During the period 1980-1986, a total of 17,396 cases of pertussis was reported to CDC by weekly telephone reports. The annual incidence of reported pertussis rose during this period from 0.5 cases per 100,000 population to 1.7/100,000. Infants less than 12 months of age had the highest average annual incidence, estimated at 32 cases per 100,000. Children 1-4 years of age accounted for 25% of all cases but had an average annual incidence only 1/7th that of infants. The incidence rates for all age groups increased consistently between 1982 and 1986. The most impressive relative increases occurred among older adolescents and persons 20 years of age and older. In 1986, 10% of reported cases were in this age group compared to only 5% in 1982. Rates of hospitalization and complications such as pneumonia, seizures, and encephalopathy associated with pertussis were highest in children less than 6 months of age and declined progressively with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical efficacy of a new, enhanced-potency, inactivated poliovirus vaccine.

The 1986-87 outbreak of paralytic poliomyelitis in Senegal, with 676 reported cases, provided an opportunity to evaluate the efficacy of an enhanced-potency inactivated poliovirus vaccine (N-IPV) in the Kolda region, where this vaccine has been used since 1980. 89 cases, confirmed to have poliomyelitis with residual paralysis, were enrolled in a case-control study, up to 5 matched controls being obtained for each case. The clinical efficacy for one dose of N-IPV was 36% (95% confidence interval 0%, 67%) and for two doses was 89% (95% CI 62%, 97%).

Congenital rubella syndrome in the United States, 1970-1985. On the verge of elimination.

The National Congenital Rubella Syndrome Registry, a passive surveillance system, and the Birth Defects Monitoring Program, a newborn hospital discharge data set, are used to monitor the incidence of congenital rubella syndrome in the United States. Reports to the registry contain clinical and laboratory data which allow cases to be classified into six categories according to the likelihood of having congenital rubella syndrome. The monitoring program records newborn discharge diagnoses, without detailed information, of a nonrandom sample of about one fourth of the births in the United States annually. To evaluate the two systems and to estimate the actual incidence of congenital rubella syndrome, the authors collected hospital discharge summaries on all cases as reported by the monitoring program from 1970-1985 and classified them by the registry criteria. Of the 392 cases reported to the monitoring program during 1970-1985, 24% (n = 93) could be classified as confirmed or compatible compared with 79% (n = 415) of the 526 cases reported to the registry (rate ratio = 3.3; 95% confidence interval (CI) 2.9-3.8). Diagnosis of congenital rubella syndrome was made during the neonatal period for 68% (263 of 389) registry cases for whom such data were available. When the Lincoln-Peterson capture-recapture method of estimating population size for independent surveillance systems was used, an estimated 1,064 confirmed and compatible cases (95% CI 668-1,460) diagnosed during the neonatal period occurred during 1970-1979, for an average of 106 cases per year. During 1980-1985, an estimate of 122 neonatal confirmed and compatible cases (95% CI 8-236) occurred, for an average of 20 cases per year. A downward secular trend in the incidence of congenital rubella syndrome beginning in 1980 was observed. The registry detected 22% of all neonatal confirmed and compatible cases, the monitoring program detected 8%, and the two systems combined detected a total of 28%. The results indicate that congenital rubella syndrome may be on the verge of elimination in the United States.

Patterns of transmission in measles outbreaks in the United States, 1985-1986.

Since the licensing of measles vaccine in 1963, the incidence of reported measles in the United States has declined to less than 2 percent of previous levels. To characterize the current epidemiology of measles in the United States, we analyzed measles outbreaks that occurred during 1985 and 1986. There were 152 outbreaks (defined as five or more cases related epidemiologically), which accounted for 88 percent of the cases reported during those two years. There were two major types of outbreaks: those in which most of the cases occurred among preschool-age children (those under 5 years of age) (26 percent) and those in which most of the cases occurred among school-age persons (those 5 to 19 years of age) (67 percent). The outbreaks among preschool-age children ranged in size from 5 to 945 cases (median, 13); a median of only 14 percent of the cases occurred in vaccinated persons, and a median of 45 percent of the cases were classified as preventable according to the current strategy. Outbreaks among school-age persons ranged in size from 5 to 363 cases (median, 25); a median of 60 percent of the cases occurred in vaccinated persons, and a median of only 27 percent of the cases were preventable. The outbreaks among preschool-age children indicate deficiencies in the implementation of the national measles-elimination strategy. However, the extent of measles transmission among highly vaccinated school-age populations suggests that additional strategies, such as selective or mass revaccination, may be necessary to prevent such outbreaks.

Vitamin A levels and mortality among hospitalized measles patients, Kinshasa, Zaire.

Treatment with high dose vitamin A has recently been recommended for children with measles in communities where vitamin A deficiency is a recognized problem. However, the relationship between vitamin A and measles mortality has not been clearly established. We studied serum vitamin A levels in 283 children less than or equal to 5 years of age admitted to Mama Yemo and Kalembe Lembe Hospitals in Kinshasa, Zaire, between January and March, 1987. Vitamin A levels were determined by high performance liquid chromatography. Vitamin A levels ranged from less than 5 to 63 micrograms/dl (median, 8). The overall case-fatality rate was 26 per cent. On univariate analysis, age less than 24 months, pneumonia on admission, lymphopenia (less than 2000/mm3), and lower vitamin A levels were associated with death during hospitalization. In a multivariate logistic regression model, a vitamin A level less than 5 micrograms/dl was associated with fatal outcome for children younger than 24 months old (relative risk = 2.9, 95 per cent CI 1.3, 6.8), but not for older children. Further studies are needed to determine whether low vitamin A levels predispose children to severe measles and the role of vitamin A supplements in the prevention of measles mortality.

Risk factors for community- and household-acquired pertussis during a large-scale outbreak in central Wisconsin.

To identify risk factors associated with community- and household-acquired pertussis, we studied 61 households (HHs) with members with culture-positive illnesses and compared their characteristics with 58 neighborhood control-HHs and 62 randomly selected control-HHs. Case-HHs were more likely than either control group to have members 12-18 y of age (P less than .01); these individuals accounted for 34% of all primary cases. A history of exposure outside the home was the most important predictor of community-acquired infection (P less than .001), with adolescents being at higher risk than other age-groups (odds ratio, 3.2; P less than .001). After known exposure to a culture-positive case in the same HH, the risk of illness was unrelated to age; lengthy delays in initiating erythromycin therapy and prophylaxis were the only factors associated with secondary spread (P less than .01). The risk of pertussis may be related more to the likelihood of exposure than to age-related increases in susceptibility, and the risk can be reduced with appropriate use of erythromycin.