Seasonality of coronary artery deaths in New South Wales, Australia

BACKGROUND

Complex temporal variations in coronary deaths, including diurnal, weekly, and seasonal trends, have been reported worldwide.

OBJECTIVE

To describe the magnitude of seasonal changes in coronary artery deaths in New South Wales, Australia.

DESIGN

Hospital morbidity data, mortality statistics, and meteorological data were modelled using time series techniques to determine seasonality of coronary deaths. Data were also analysed to determine whether there was an increase in deaths before or after the Christmas and New Year holidays.

RESULTS

A clear seasonality of coronary deaths was shown, with a peak in July. A mean of 2.8 excess coronary deaths per 100 deaths was estimated to occur from June to August each year, with a mean annual excess of 224 winter deaths a year. Mortality data did not show an increase in coronary death ratios before (p = 0.626) or after (p = 0.813) the Christmas and New Year holidays in December.

CONCLUSIONS

There is a higher incidence of coronary deaths in winter, which may reflect winter respiratory infections, the direct effect of cold, seasonal changes in lipid concentration, and other factors associated with winter. Hospitals should have contingency plans during the winter months to manage larger numbers of cardiac admissions.

Appropriateness of red blood cell transfusions in major urban hospitals and effectiveness of an intervention

OBJECTIVES

To assess the appropriateness of red blood cell (RBC) transfusions and the effectiveness of an intervention to reduce inappropriate RBC transfusions.

DESIGN

Medical record audit by hospital staff using a data form, before and after randomly allocated interventions (letter only or letter+visit). Criteria for assessing appropriateness of RBC transfusions were based on a systematic literature review.

SETTING

Ten major urban hospitals in Sydney, New South Wales, in 1998 and 1999.

SUBJECTS

Medical records of up to 120 patients at each hospital (n=1117).

INTERVENTIONS

Letter-only (5 hospitals)--results of first audit at the hospital mailed to chief executive officer of that hospital; letter+visit (5 hospitals) results of first audit at the hospital presented by the research team to a meeting of that hospital's staff, and then mailed to the chief executive officer.

MAIN OUTCOME MEASURE

Proportion of RBC transfusions assessed as inappropriate.

RESULTS

At first audit, 35% of RBC transfusions were assessed as inappropriate. Small reductions in inappropriate transfusions were found at the second audit, but the change was significant only for the hospitals receiving the letter-only intervention. About 5% of patients received a single RBC unit; 40% of single-unit transfusions were inappropriate. More RBC transfusions were inappropriate in surgical patients than in those treated by other specialties.

CONCLUSIONS

About a third of RBC transfusions were assessed as inappropriate. The interventions had only a small effect on transfusion appropriateness.

Folate fortification: potential impact on folate intake in an older population

OBJECTIVE

To examine the potential impact of different models of folate fortification of Australian foods on the folate intakes of older Australians.

DESIGN

Dietary data were collected using a food frequency questionnaire from people attending a population-based health study.

SETTING

Two postcode areas west of Sydney, Australia.

SUBJECTS

A total of 2895 people aged over 49 y, obtained from a door knock census (79% of 3654 subjects examined).

MAIN OUTCOME MEASURES

The folate intake in this population was estimated using four different models: (1) pre-fortification folate values; (2) current voluntary folate fortification in Australia; (3) universal fortification of all foods permitted to add folate, at 25% recommended dietary intake (RDI) per reference serve; and (4) universal fortification of all foods permitted to add folate, at 50% RDI per reference serve. The increased bioavailability of synthetic folic acid (SFA) was included in the analysis.

RESULTS

At current voluntary folate fortification, approximately 65% of this population consume 320 microg dietary folate equivalents (DFE) or more per day from diet and supplements, and 0.4% (n=10) consume greater than the recommended upper safety level of 1000 microg from SFA. More than 95% of this older population would be expected to consume more than 320 microg DFE from diet and supplements with universal fortification at 50% of the RDI, and 0.5% (n=14) may consume greater than 1000 microg/day of SFA.

CONCLUSIONS

There is unlikely to be a large increase in the proportion of older persons who are likely to consume more than the upper safety level of intake with universal folate fortification. As most of those who currently or are predicted to consume over 1000 microg SFA take supplements containing folic acid, it is highly recommended that vitamin B12 be included in any vitamin supplements containing folate.

SPONSORSHIP

This study was supported by the Australian National Health and Medical Research Council (NHMRC).

Peroxisome proliferator-activated receptor gamma ligands inhibit estrogen biosynthesis in human breast adipose tissue: possible implications for breast cancer therapy

Estrogen biosynthesis is catalyzed by aromatase cytochrome P-450 (the product of the CYP19 gene). Adipose tissue is the major site of estrogen biosynthesis in postmenopausal women, with the local production of estrogen in breast adipose tissue implicated in the development of breast cancer. In human adipose tissue, aromatase is primarily expressed in the mesenchymal stromal cells and is a marker of the undifferentiated preadipocyte phenotype. Aromatase expression in adipose tissue is regulated via the distal promoter I.4, under the control of glucocorticoids and class I cytokines such as oncostatin M, interleukin 6, and interleukin 11, as well as tumor necrosis factor alpha. These cytokines, which are expressed in adipose, also inhibit adipocyte differentiation. Therefore, we hypothesized that factors which stimulate adipocyte differentiation should inhibit aromatase expression. These factors include synthetic peroxisome proliferator-activated receptor gamma (PPARgamma) ligands such as thiazolidinediones, e.g., troglitazone and rosiglitazone (BRL49653) and the endogenous PPARgamma ligand 15-deoxy-delta12,14-prostaglandin J2. We have demonstrated by measurement of aromatase activity and by reverse transcription-PCR/Southern blotting that these PPARgamma ligands inhibit aromatase expression in cultured breast adipose stromal cells stimulated with oncostatin M or tumor necrosis factor alpha plus dexamethasone in a concentration-dependent manner, whereas a metabolite of troglitazone that does not activate PPARgamma has no effect. We have also shown that troglitazone inhibits luciferase activity of reporter constructs containing various lengths of the upstream region of promoter I.4 transfected into mouse 3T3-L1 preadipocyte mesenchymal cells, whereas the troglitazone metabolite does not. Because local estrogen production in breast fat is implicated in breast cancer development in postmenopausal women, the actions of PPARgamma ligands suggest that they may have potential therapeutic benefit in the treatment and management of breast cancer.

Getting new evidence into medicine

The rate of transfer of the knowledge gained from health and medical research into evidence-based practice is determined by many factors. Preconditions for the uptake of new evidence are the availability of good evidence, ready access to the evidence, a supportive organisational environment, and effective mechanisms for promoting knowledge uptake. Evidence-based medicine is being promoted in Australia by a body of enthusiastic clinicians, public health practitioners and consumer advocates, supported by initiatives from national, State and local healthcare services and professional bodies. The short to medium term future of evidence-based medicine in Australia is likely to be shaped by three major factors: a reduction in cost and technical barriers which limit access to computerised databases; a trend towards shared decision-making between clinicians and patients; and increased demand for information to fill the gaps in research-based evidence on specific problems.

Regulation of sulphotransferase expression in the endometrium during the menstrual cycle, by oral contraceptives and during early pregnancy

The endometrium plays a key role in reproduction, and this function is tightly regulated by endogenous and xenobiotic steroids. Sulphation, catalysed by members of the sulphotransferase (SULT) enzyme family, is a major deactivating mechanism for steroid hormones and we have investigated the expression and regulation in vivo of SULT in the human endometrium. In the normal cycling endometrium, expression of the phenol sulphotransferases SULT1A1 and SULT1A3 and the oestrogen sulphotransferase SULT1E1 were observed, with SULT1A1 and SULT1E1 expression being higher in the luteal phase than in the follicular phase. No expression of the hydroxysteroid sulphotransferase SULT2A1 was detected at any time in the endometrium. In endometrium from women taking the combined oral contraceptive pill (OCP), SULT1E1 expression was virtually absent, and SULT1A1 expression was substantially reduced. Similarly, in early pregnancy (i.e. first trimester) endometrium, SULT1E1 expression was absent, although SULT1A1 and SULT1A3 expression were unaffected. Our results with normal endometrium support in-vitro data showing that SULT1E1 expression is regulated by progesterone. However, the data obtained from OCP and early pregnancy endometrium suggest that factors other than the concentration of circulating progesterone are involved in the regulation of the expression of this important enzyme in the endometrium.

Design, production and characterization of antibodies discriminating between the phenol- and monoamine-sulphating forms of human phenol sulphotransferase

1. Phenol sulphotransferases (PSTs) are important enzymes in xenobiotic and endobiotic detoxication, and a key component of the body's chemical defence mechanism. 2. Human phenol-(P-PST) and monoamine-(M-PST) sulphating forms of PST share 93% amino acid sequence identity, and to date the various antibodies produced against PSTs all recognize both enzymes. 3. We have identified two peptides based on the cDNA-derived amino acid sequences of human P-PST and M-PST, which elicited for the first time antibodies capable of discriminating between these highly homologous enzymes. 4. These antibodies represent valuable tools for studying the expression, distribution and function of human phenol sulphotransferases.

Reduced platelet phenolsulphotransferase activity towards dopamine and 5-hydroxytryptamine in migraine

OBJECTIVE

The sulphation of the neurotransmitters dopamine and 5-hydroxytryptamine, and of the prototypical xenobiotic 4-nitrophenol, by phenolsulphotransferases was measured in platelet homogenates prepared from a group of migraine sufferers and a group of control subjects.

RESULTS

The activity of the M form of phenolsulphotransferase, responsible for the sulphation of dopamine and 5-hydroxytryptamine was significantly reduced in the migraine population, by 28% with dopamine as substrate and by 20% with 5-hydroxytryptamine. The activity of the P form of the enzyme towards 4-nitrophenol was the same in both groups. We also report that the selective inhibition of P form phenolsulphotransferase by red wine is much more potent than previously thought, with a 2000-fold dilution of dealcoholised red wine having the ability to inhibit sulphation by this enzyme by 50%.

CONCLUSION

Our findings suggest that a reduced capacity for sulphation and inactivation of biogenic amines and catecholamines may be related to susceptibility to migraine.

Assessing utilisation of health technologies: coronary artery bypass graft surgery in New South Wales

The New South Wales health system aims to provide the most effective and efficient health care in a context of scarce resources and increasing availability of expensive technologies. The aging of the population and the management of chronic disease place further demands on the health system. Examination of the pattern of provision of services over time and between groups can serve to illustrate trends in clinical management practices which may affect other elements of the health system. In this paper we report an evaluation of the patterns of coronary artery bypass graft surgery (CABG) in New South Wales, within subgroups of the population and over time. The results demonstrate increased utilisation of this procedure in the population over recent years, particularly among the older age groups. We found differences in procedure rates between geographic areas which suggest that there are differences in the management of ischaemic heart disease between population subgroups. These patterns are examined in the context of the available literature on the health outcomes of CABG relative to other management options for ischaemic heart disease.

The health effects of swimming at Sydney beaches. The Sydney Beach Users Study Advisory Group

OBJECTIVES

The purpose of the study was to determine the health risks of swimming at ocean beaches in Sydney, Australia.

METHODS

From people attending 12 Sydney beaches in the period from December 5, 1989 to February 26, 1990, we recruited a cohort of 8413 adults who agreed to participate in this study. Of these, 4424 were excluded either because they had been swimming in the previous 5 days or because they reported a current illness. Of the remainder, 2839 successfully completed a follow-up telephone interview conducted within 10 days after recruitment. We recorded reported respiratory, gastrointestinal, eye, and ear symptoms and fever that occurred within the 10 days between initial interview on the beach and the follow-up interview.

RESULTS

A total of 683 participants (24.0%) reported experiencing symptoms in the 10 days following initial interview. Of these, 435 (63.7%) reported respiratory symptoms. Swimmers were almost twice as likely as nonswimmers to report symptoms. There was a linear relationship between water pollution and all reported symptoms with the exception of gastrointestinal complaints.

CONCLUSIONS

Swimmers at Sydney ocean beaches are more likely to report respiratory, ear, and eye symptoms than beachgoers who do not swim. The incidence of these symptoms increases slightly with increasing levels of pollution.

Variation in selected childhood surgical procedures: the case of tonsillectomy and management of middle ear disease

We examined rates of the most common ear, nose and throat (ENT) surgical procedures among NSW residents under 15 years of age, against a background of concern for the relevance of differences in clinical practice to cost and quality of health care. We found significant (P < 0.01) increases in the rate of procedures involving myringotomy (from 5.8/1000 to 7.6/1000) or adenoidectomy (from 5.6/1000 to 6.3/1000) between 1986 and 1989/90. Over this period the proportion of ENT procedures which involved myringotomy also increased significantly (P < 0.01) from 53 to 60%. We found significant (P < 0.01) differences in procedural rates between health areas when aggregated into inner and outer metropolitan and rural groups with the mean rate of procedures involving myringotomy highest in the outer metropolitan group in both years. The difference was not due to variation in patient insurance status, per capita hospital bed or staff numbers. We found no evidence that the National Health and Medical Research Council Tonsillectomy and Adenoidectomy Guidelines (first published in 1982) have been effective in influencing clinical practice. The rate of tonsillectomy had been declining in NSW since the late 1970s but has remained stable in recent years. Surgical intervention for middle ear disease is increasing.

Diagnostic procedures and health outcomes. Upper gastrointestinal tract investigations in the elderly

OBJECTIVES

To examine the use of upper gastrointestinal endoscopy in people 65 years of age and over in New South Wales, and compare its use between geographic areas, sex and age groups. Also, to investigate the relationship between endoscopy use and peptic ulcer mortality.

DESIGN

A retrospective review of upper gastrointestinal tract (GIT) endoscopy hospital separation data for NSW from 1986 to 1989-1990 and peptic ulcer mortality data from 1979 to 1989.

MAIN OUTCOME MEASURES

Rates per 1000 population aged 65 years and over were calculated for upper GIT endoscopy for each of the four-year age groups and by sex. Peptic ulcer and other digestive system disease rates for endoscopy patients were determined. Correlations between hospital standardised separation rates for endoscopy and standardised mortality rates for gastric cancer and peptic ulcers were calculated. Age and sex standardised death rates were calculated for each year between 1979 and 1989, and changes in death rates over time were determined by regression analysis.

RESULTS

The rate of endoscopies increased significantly (P < 0.001) over the period 1986 to 1989-1990, with the highest rate and greatest increase occurring in patients aged 70 years and over. Men had significantly higher endoscopy rates than women (P < 0.001). Geographic variations in the use of endoscopy were found and were not explained by geographic differences in the proportion of peptic ulcers diagnosed, deaths from peptic ulcers or malignant neoplasms. Despite the increase in endoscopies performed, there was no corresponding significant increase in the rate of peptic ulcers detected. Between 1979 and 1989 peptic ulcer mortality rates for women over 74 years of age increased significantly (P < 0.05); the rate for men did not change.

CONCLUSION

Many endoscopies are performed in people aged 65 years and over in NSW and there has been a substantial increase in endoscopy rates in recent years. While the increase in upper GIT endoscopy may have resulted in a number of health benefits, it does not appear to have resulted in a reduction in peptic ulcer related mortality.

An outbreak of Norwalk-like gastroenteritis associated with contaminated drinking water at a caravan park

During the 1989 Christmas holiday period, a large outbreak of gastroenteritis occurred among persons staying at a caravan park in southern New South Wales. Review of local hospital records found that 77 per cent of patients presenting with infective diarrhoea between 29 December and 3 January had stayed at the caravan park. In a retrospective cohort study we compared rates of illness among caravan park patrons exposed to different water sources. Stools were tested for pathogens and convalescent sera for viral antibodies. Rain and reticulated river water sampled from the caravan park were tested for bacteria and viruses. Of 351 persons interviewed at the caravan park, 305 (87 per cent) reported an illness characterised by diarrhoea, vomiting and abdominal pain. Of 196 persons who used reticulated river water for drinking or ablutions, 175 (89 per cent) became ill compared with 47 of 72 persons (65 per cent) who did not use this water (relative risk 1.4, 95 per cent confidence interval 1.2 to 1.6). The outbreak was probably caused by a 27-28 nm small round structured virus found in the stool from one ill person. High levels of faecal coliforms in the reticulated river water and enterovirus in sediment samples suggest that the outbreak was caused by sewage contaminating the reticulated river water through a break in the pipe directly over the underground water tanks. To prevent such outbreaks, poor water and sewerage system layouts should be avoided and nonpotable water should be clearly labelled. Where feasible, all camping-ground water should stem from town supplies.

Teenage pregnancy and fertility in New South Wales: an examination of fertility trends, abortion and birth outcomes

This paper reviews the data available in New South Wales on teenage fertility rates and pregnancy outcomes. Teenage births comprise six per cent of all births in New South Wales, but they constitute a significant public health problem because they are associated with elevated rates of adverse pregnancy outcomes, which include low birthweight, perinatal death and pre-eclampsia. Risk is concentrated in females under 18 years of age. Pregnancy outcomes for females aged 18 to 19 years are similar to those of women aged 20 to 24 years. Teenage fertility rates have remained stable since the mid-1980s, following a decline which began in the early 1970s. There are large geographic variations in teenage fertility within the state, with the highest rates in the far west of New South Wales and in western Sydney. Teenage pregnancy in New South Wales (as distinct from fertility which reflects births) cannot be assessed accurately because of the lack of information on terminations of pregnancy. However, available data suggest that teenage pregnancy rates have not increased during the 1980s.

Mycobacterial disease and AIDS in New South Wales

OBJECTIVE

To determine the coincidence of mycobacterial disease and acquired immunodeficiency syndrome (AIDS), and whether persons with mycobacterial disease and human immunodeficiency virus (HIV) infection differ from those with mycobacterial disease alone, by age, sex and country of birth.

DESIGN

A descriptive study.

PARTICIPANTS

Persons on the NSW Tuberculosis Register in 1989 and those on the NSW AIDS database in 1982-1989.

MAIN OUTCOME MEASURE

Coincident appearance on the Tuberculosis Register and the AIDS database.

RESULTS

People with atypical mycobacterial infection and HIV infection were younger and more likely to be male compared with those with mycobacterial disease alone. There was a strong association between mycobacterial disease and HIV infection. Of 438 patients newly diagnosed with mycobacterial disease in 1989, 75 (17.1%) had HIV infection. Of 318 tuberculosis patients, 8 (2.5%) had HIV infection, and of 120 patients with atypical mycobacterial infection, 67 (55.8%) had HIV infection.

CONCLUSION

Close monitoring of HIV patients for mycobacterial infection, and chemoprophylaxis for persons infected with HIV who have positive Mantoux test results will assist in the control of mycobacterial disease. HIV testing and counselling should be considered for all persons with mycobacterial disease.

Rabies case in New South Wales, 1990: public health aspects

OBJECTIVES

To identify the source of rabies in the recent case in New South Wales, and to determine the need for post-exposure rabies prophylaxis among contacts of the patient.

DESIGN

Information was obtained by face-to-face interview of the dead girl's family and face-to-face and telephone interviews using a questionnaire of health care workers. Other information was gathered from overseas and local sources through telephone and facsimile contact.

RESULTS

The girl had migrated from Vietnam in 1984 to Hong Kong, and from there in 1986 to Australia. No evidence of contact with a rabid animal in Australia or Hong Kong was found. There had also been no organ donations from the girl. Four health care workers were given post-exposure rabies prophylaxis.

CONCLUSIONS

Because of the lack of evidence of animal contact in Australia and the fact that extremely long incubation periods for rabies have been documented, it was considered that the most likely source of the rabies virus was North Vietnam. Genetic studies of the virus also supported a South-East Asian source. Nevertheless the presumed incubation period--at least six years and four months--is one of the longest recorded.

Underreporting of AIDS, New South Wales, 1988-1989

OBJECTIVE

To determine the completeness of medical practitioner reporting of patients with acquired immunodeficiency syndrome (AIDS) in New South Wales and the reasons for underreporting.

DESIGN

We compared the number of patients with AIDS reported to the National AIDS Register by medical practitioners from 1 July 1988 to 23 November 1989 with numbers detected from the National Zidovudine Register, AIDS specialist medical practitioner records, death certificates and the Sydney AIDS Prospective Study database. We asked the AIDS specialist medical practitioners to suggest why some patients may not be reported.

MAIN OUTCOME MEASURE

The number of persons known to have AIDS and the source from which they were detected.

RESULTS

We found 457 recorded cases of AIDS in which the diagnosis was made during the study period. Of these 457 cases, 373 (81.6%) had been reported by medical practitioners and 84 had not. Of these 84 cases, 40 were detected from the National Zidovudine Register, 24 from the records of AIDS specialist medical practitioners, 18 from death certificates and two from the Sydney AIDS Prospective Study. Reporting rates among hospitals ranged from 38.5% to 95.7%. We estimated that the true number of persons diagnosed with AIDS in New South Wales over the study period was 476. The main reasons given by the doctors for not reporting persons with AIDS were difficulties with reporting procedures and the complicated AIDS case definition, concerns about maintaining patient confidentiality and inadequate Health Department feedback on AIDS surveillance data.

CONCLUSIONS

At least 18.4% of the AIDS cases we detected were not reported by medical practitioners in New South Wales. More accurate information on the incidence of AIDS could be obtained if the Health Department regularly contacted AIDS specialist medical practitioners for unreported cases, simplified the reporting process, stressed the confidentiality provisions for AIDS reporting and provided feedback to reporting medical practitioners.

Histologic types of benign breast disease and the risk for breast cancer. The Cancer and Steroid Hormone Study Group

Specific histologic types of benign breast disease (BBD) may increase breast cancer risk. The authors analyzed data from a population-based, case-control study of women aged 20 to 54 with newly diagnosed breast cancer and control subjects randomly selected from the general population. A panel of pathologists classified the histologic findings of biopsy slides for 433 women with breast cancer and 261 control subjects, all of whom had a history of biopsy for BBD, as to the presence of epithelial hyperplasia, atypia, and other histologic features. When compared with women who had never had a breast biopsy, women with BBD without hyperplasia had an odds ratio of 1.5 (95% confidence limits [CL] 1.3 to 1.9), women with hyperplasia without atypia had an odds ratio of 1.8 (CL = 1.3, 2.4), and women with hyperplasia and atypia had an odds ratio of 2.6 (CL = 1.6, 4.1). Fibroadenoma was an independent risk factor for breast cancer (odds ratio = 1.7; CL = 1.1, 2.5). These findings suggest that women with BBD with epithelial hyperplasia either with or without atypia and women with fibroadenoma should be monitored carefully because of their elevated risk for breast cancer.

Improving surveillance of infectious diseases in New South Wales

OBJECTIVE

To determine the feasibility of laboratory reporting of infectious diseases and to compare the value of this system with the existing medical practitioner notification system.

DESIGN

A sample of notifications was selected from medical practitioner notifications and was compared for both completeness and timeliness of notification with a sample of notifications obtained through the Laboratory Infectious Diseases Surveillance Project.

SETTING

The New South Wales Health Department and the Public Health Unit of the Eastern Sydney Area Health Service.

PARTICIPANTS

Medical practitioners forwarding notifications of infectious diseases to the New South Wales Health Department and laboratories participating in the Laboratory Infectious Diseases Surveillance Project.

MAIN OUTCOME MEASURES

We counted the number of infectious diseases reported by medical practitioners and participating laboratories and estimated the proportion of these diseases which were common to both sources of data. We also estimated the time taken between the diagnosis of a notifiable infectious disease and the receipt of the notification by the Medical Officer of Health.

RESULTS

There was substantial underreporting of notifiable infectious diseases by medical practitioners. During the study there were 461 cases of a notifiable disease reported by either medical practitioners or by participating laboratories. Of these cases, 75% were reported only by laboratory staff, 20.2% were reported by medical practitioners alone and 4.8% of cases were reported by both laboratory staff and medical practitioners. The Medical Officer of Health received the reports from the participating laboratories within a significantly shorter time than the notifications from medical practitioners.

CONCLUSION

The use of infectious disease notifications by laboratories can substantially improve the surveillance of infectious diseases.

Measures of sexual behavior and the risk of pelvic inflammatory disease

A women's sexual behavior affects her risk of acquiring pelvic inflammatory disease, but the risks have not been well characterized. To study the association between pelvic inflammatory disease and sexual behavior, we analyzed data from a multicenter, case-control study involving 712 women hospitalized with an initial episode of pelvic inflammatory disease and 2719 hospitalized control women without a history of pelvic inflammatory disease. Study participants provided information on their frequency of intercourse, number of recent sexual partners, and previous history of gonorrhea. Logistic regression methods were used to adjust for confounding factors. Women who reported having four or more sexual partners were over three times more likely to be hospitalized for pelvic inflammatory disease (relative risk 3.4; 95% confidence interval 2.2-5.3) than were women who reported only one recent sexual partner. To a lesser extent, frequent sexual intercourse and history of gonorrhea also increased a woman's risk of pelvic inflammatory disease. Frequent intercourse was a strong risk factor for pelvic inflammatory disease among a subgroup of women who were at low risk for acquiring a sexually transmitted disease: Married women with one recent sexual partner with intercourse six or more times per week had a risk of pelvic inflammatory disease of 3.2 (1.4-7.2) compared with similar women having intercourse less than once per week. Frequent intercourse, which does not by itself increase the risk of acquiring a sexually transmitted disease, may increase a woman's risk of pelvic inflammatory disease.

Estrogen replacement therapy and the risk of endometrial cancer: remaining controversies

To examine the relationship between exogenous estrogen administration and endometrial cancer, we used data from the Cancer and Steroid Hormone Study, a multicenter, population-based case-control study. Estrogen replacement therapy for greater than or equal to 2 years was associated with an increased risk of both localized and extrauterine cancer (relative risk = 2.8, 95% confidence limits 1.6, 4.6; relative risk = 2.9, 95% confidence limits 0.9, 9.4, respectively). However, the latter finding was based on a small number of cases in which estrogen was used. Women who underwent estrogen replacement therapy for greater than or equal to 2 years had significantly elevated risks of endometrial cancer (2.1 for 2 to 5 years and 3.5 for greater than or equal to 6 years). An elevated risk persisted for greater than or equal to 6 years after discontinuation of therapy. Women who exclusively used conjugated equine estrogen preparations less than or equal to 0.625 mg had no increased risk of endometrial cancer. A history of oral contraceptive use appeared to reduce the risk of endometrial cancer associated with estrogen replacement therapy. However, these latter two potentially important findings were based on a small number of cases in which hormones were used.

Pregnancy, breast feeding, and oral contraceptives and the risk of epithelial ovarian cancer

To quantify the effects of cumulative months of pregnancy, breast feeding, and oral contraceptive use on the risk of developing epithelial ovarian cancer, the authors used data collected for the Cancer and Steroid Hormone Study--a multicenter, population-based, case-control study. Detailed reproductive histories were obtained from 436 women aged 20-54 with epithelial ovarian cancer newly diagnosed between December 1980 and December 1982, and from 3833 women aged 20-54 selected at random from the same geographic areas. Estimated relative risks of epithelial ovarian cancer were 0.6 (95% confidence interval (CI) 0.5-0.8) for women who had ever been pregnant, 0.6 (95% CI 0.5-0.8) for women who had ever breast fed, and 0.5 (95% CI 0.5-0.7) for women who had ever used oral contraceptives. Logistic regression analysis revealed a strong trend in decreasing risk of epithelial ovarian cancer with increasing cumulative months of pregnancy; this effect was less pronounced in women aged 50-54 than in younger women. In contrast, a marked reduction in risk was associated with ever having breast fed or used oral contraceptives, while the decrease in risk from additional months of either of these exposures was less than that for pregnancy.

Research on infertility: definition makes a difference. The Cancer and Steroid Hormone Study Group

Although different definitions of infertility are used, research findings based on various definitions have not been systematically compared. To contrast the impact of five definitions of infertility on research findings, the authors analyzed data from the control group (randomly selected US women aged 20-54 years) of the Cancer and Steroid Hormone Study (1980-1983). For all definitions, an absence of recognized conception was the outcome of interest. Specifically, the authors examined the effect of various definitions of infertility on demographic characteristics of women classified as infertile, prevalence of a history of infertility, age at infertility classification, and cumulative incidence of conception after infertility classification. Results indicated that women classified as infertile by definitions based on unprotected intercourse for 12 months and unprotected intercourse for 24 months were more likely to be black, less educated, and classified as infertile at younger or older ages that women classified by alternative definitions. The prevalence of a history of infertility ranged from 6.1% (physician diagnosis) to 32.6% (unprotected intercourse for 12 months). For the definitions based on unprotected intercourse for 12/24 months and for physician diagnosis, the cumulative incidence of conception by greater than 120 months after infertility classification was 86.3%, 76.7%, and 75.4%, respectively. The authors conclude that the definition of infertility has an impact on research findings related to which and how many women are classified as infertile, the age at infertility classification, and the probability of future conception.

The independent associations of parity, age at first full term pregnancy, and duration of breastfeeding with the risk of breast cancer. Cancer and Steroid Hormone Study Group

Although the important influence of a woman's reproductive history on her risk of breast cancer is widely recognized, it is not clear whether this is wholly accounted for by the age at her first full-term pregnancy, or whether there are additional, independent influences of breastfeeding or number of children. To examine the respective contributions to the risk of breast cancer of these reproductive factors, we used logistic regression methods to analyze data from a multicenter case-control study, the Cancer and Steroid Hormone Study. Included in the analysis were 4599 women, 20-55 years of age, identified as having an initial diagnosis of breast cancer by one of eight collaborating population-based cancer registries. The 4536 controls were women of similar ages selected by random dialing of households with telephones in the same eight areas. As expected, age at first full-term pregnancy exerted a strong influence on the risk of breast cancer. However, after it and other potentially confounding factors had been controlled for, parity and duration of breastfeeding also had a strong influence on the risk of breast cancer. Compared with women of parity one, women of parity seven or greater had an adjusted relative risk of breast cancer of 0.59 (95% CL, 0.44-0.79). Compared with parous women who never breastfed, women who had breastfed for 25 months or more had an adjusted relative risk of 0.67 (0.52-0.85). These results do not support the supposed preeminent importance of age at first full-term pregnancy among the reproductive determinants of breast carcinogenesis. Resolution of this issue may have important implications for elucidating hormonal influences on breast cancer and for projecting future trends in the disease.

The intrauterine device and pelvic inflammatory disease revisited: new results from the Women's Health Study

To examine whether the risk of pelvic inflammatory disease associated with intrauterine device (IUD) use varies with a woman's sexual behavior, we analyzed data from the Women's Health Study, a hospital-based, case-control study carried out in the United States from 1976-1978. The cases were 657 women hospitalized with pelvic inflammatory disease; controls were 2566 women hospitalized with nongynecologic conditions. After controlling for confounding factors, we found no consistent differences in the risk of pelvic inflammatory disease associated with IUD use among women in different categories of gonorrhea history, frequency of intercourse, or number of recent sexual partners. However, among women with only one sexual partner, married and cohabiting women had little appreciable increased pelvic inflammatory disease risk associated with IUD use compared with those using no contraception, whereas previously and never-married women using IUDs had relative risk estimates of 1.8 and 2.6, respectively. These results suggest that women at low risk of acquiring sexually transmitted infections have little increase in the risk of pelvic inflammatory disease from use of an IUD.

Hysterectomy, tubal sterilization, and the risk of breast cancer

Studies suggest that hysterectomy and tubal sterilization may alter the function of the remaining ovaries. Conceivably, this effect could alter breast cancer risk. To investigate whether these surgeries affect breast cancer risk, the authors analyzed data collected between December 1, 1980, and April 30, 1983, in a population-based, case-control study of women aged 20-54 years, the Cancer and Steroid Hormone Study. Compared with never-sterilized women, women with hysterectomy and no remaining ovaries had a decreased risk of breast cancer (relative risk (RR) = 0.7, 95% confidence interval (CI) = 0.6-0.8). Risk was lowest in women who had their surgery before age 40 years or 15 or more years in the past; surgery at an early age provided greater protection than surgery in the distant past. Hysterectomy with one or two remaining ovaries was also inversely associated with breast cancer risk (RR = 0.8, 95% CI = 0.7-0.9), but no relation was found with age at surgery or time since surgery. Women with tubal sterilization had a slightly increased risk of breast cancer, which was of borderline statistical significance (RR = 1.2, 95% CI = 1.0-1.3). However, no relation was found with age at surgery or time since surgery. The data suggest that hysterectomy with bilateral oophorectomy decreases the breast cancer risk in women aged less than 55 years, possibly by curtailing ovarian function at a critical period. However, neither hysterectomy without bilateral oophorectomy nor tubal sterilization appears to substantially alter breast cancer risk in women of this age.

Cigarette smoking and the risk of epithelial ovarian cancer

Cigarette smoking may affect each of the currently proposed mechanisms of ovarian carcinogenesis. Whether cigarette smoking has any effect on the development of ovarian cancer has not been adequately evaluated. To study this issue, the authors examined data from the Cancer and Steroid Hormone Study, a multicenter, case-control study of gynecologic cancers conducted between December 1, 1980, and December 31, 1982, in eight geographic areas of the United States. This analysis utilized data on 494 women with newly diagnosed epithelial ovarian cancer and 4,238 population-based control women 20-54 years of age. There was no association of epithelial ovarian cancer with dose of cigarette smoking, age smoking started, time since smoking started, or time since smoking last occurred. Simultaneous adjustment for age, parity, history of oral contraceptive use, and other potentially confounding factors did not alter these results.

Consistency and plausibility in epidemiologic analysis: application to breast cancer in relation to use of oral contraceptives

Consistency and plausibility are fundamental criteria for judging cause and effect from observational studies. They are applied here to the interpretation of data from a population-based case-control study of oral contraceptives and breast cancer. A preliminary analysis of oral contraceptive use in young nulliparous women, who had no family history of either breast cancer or benign breast disease, showed a statistically significant dose-response, with long-term users (49 months or more) having an apparent 4-fold elevation in risk of early breast cancer. Further analyses, however, revealed striking inconsistencies which were biologically implausible. These effectively undermine cause and effect as an explanation for the initial finding.

Vasectomies performed by private physicians, United States, 1980 to 1984

Using data from the National Disease and Therapeutic Index, we estimated that between 1980 and 1984, 1.9 X 10(6) U.S. men had vasectomies. Men between the ages of 30 and 39 years, and white men, were more likely than others to undergo the procedure. Further national data on this popular procedure are needed.

Alcohol consumption and ovarian cancer risk

To study the influence of alcohol consumption on the risk of ovarian cancer in women under age 55, the authors examined data collected in a multicenter, population-based case-control study--the Centers for Disease Control's Cancer and Steroid Hormone Study. Between August 1981 and December 1982, 433 women 20-54 years of age with newly diagnosed ovarian cancer and 2,915 women 20-54 years of age selected at random from the same geographic areas were asked about their consumption of alcoholic beverages during the previous five years. Women who drank any alcohol during the five-year period had a risk of ovarian cancer of 0.9 (95% confidence interval (CI) = 0.7-1.2) compared with nondrinkers. Risk was not associated with the type of alcoholic beverage consumed, nor were the results affected by controlling for demographic characteristics and oral contraceptive use. Although there was no association between moderate alcohol consumption and ovarian cancer, women who drank more than about 20 drinks per week had a relative risk of ovarian cancer of 0.5 (95% CI = 0.2-0.9) compared with women who did not drink.

Nutrient intake and supplementation in the United States (NHANES II)

Data from the second United States Health and Nutrition Examination Survey (NHANES II) suggest that almost 35 per cent of the US population 18 to 74 years of age takes vitamin/mineral supplements regularly. Both higher nutrient intake and use of vitamin supplementation are associated with older ages, higher income, higher education level, and White race. Accounting for differences associated with sex, age, race, income, and education, persons with higher nutrient intakes remain more likely to take vitamin supplements.

Characteristics of vasectomies performed in selected outpatient facilities in the United States, 1980

In 1981 the American Association of Gynecologic Laparoscopists and the Division of Reproductive Health, Centers for Disease Control, jointly conducted a study of vasectomies performed in outpatient facilities in 1980 in the United States. One hundred twenty-nine facilities that responded to either a mailed questionnaire or a telephone interview stated that vasectomies were performed there in 1980. The average cost was $273, with a range of $50-1,000. Facilities differed markedly in the use of anesthesia. Freestanding surgical centers reported the use of general anesthesia for 29% of the vasectomies. Other types of facilities were more likely to use local or regional anesthesia. Our data suggest areas for further research to improve the availability and safety of vasectomy.

Oral contraceptives and breast cancer in young women

The relation between use of oral contraceptives (OCs) by young women and their risk of breast cancer before 45 years of age was investigated by analysis of data from a population-based, case-control study conducted in eight geographic regions of the United States. 2088 women with breast cancer diagnosed between Dec 1, 1980, and Dec 31, 1982, were compared with 2065 controls selected during the same period. There was no significant increase or decrease in the risk of breast cancer for OC users according to age at first use or subsequent duration of use, even for women who first used OCs before the age of 20 years and who continued to use them for more than 4 years. Risk was not altered significantly for women who used OCs with high progestagen "potency" before the age of 25 years (even when duration of use exceeded 6 years), for those who used OCs before first-term pregnancy (even when duration of use exceeded 4 years), or for OC users according to age at diagnosis. These results suggest that use of OCs by young women in the United States has no effect on the aggregate risk of breast cancer before 45 years of age.

Hysterectomy performed within 1 year after tubal sterilization

In the United States, approximately 650,000 women of reproductive age undergo tubal sterilization each year and some of these women later have hysterectomies. Little is known about risk factors for having hysterectomy after tubal sterilization. For examination of this issue, we analyzed data from the Collaborative Review of Sterilization, an ongoing multicenter prospective study designed to assess the safety and efficacy of female sterilization operations. In 1979 and 1980, 4002 women 15 to 44 years of age had interval tubal sterilization; of these women, 64 had hysterectomies within 15 months, which yielded a cumulative incidence of 1.6%. Women with a history of menstrual complaints, leiomyomata, ovarian cysts, or endometriosis before their tubal sterilization had an increased risk of hysterectomy, compared with women without such a history. However, 98% of women with a history of these conditions did not have a hysterectomy within 15 months after tubal sterilization. Further follow-up of these women should help to better delineate their long-term risks.

The mortality risk associated with hysterectomy

To study the risks of mortality associated with hysterectomy that are specific to age, race, surgical approach, and associated conditions, we used data collected by the Commission on Professional and Hospital Activities during 1979 and 1980. Four hundred seventy-seven deaths were recorded among 317,389 women having abdominal hysterectomies and 46 deaths among 119,972 women having vaginal hysterectomies. The mortality rates for hysterectomy, standardized for age and race, were higher for procedures associated with pregnancy or cancer than for procedures not associated with these conditions (29.2, 37.8, and 6.0 per 10,000 procedures, respectively). Hysterectomies associated with pregnancy or cancer constituted 8% of all hysterectomies performed. However, 61% of all deaths occurred in women with pregnancy- or cancer-related conditions. The mortality rate associated with hysterectomy increased with age and was twice as high among black women.

Regret after decision to have a tubal sterilization

To determine characteristics associated with regretting sterilization that can be determined preoperatively, we analyzed data from the Collaborative Review of Sterilization (CREST), a multicenter, prospective, observational study. Of 5022 women, 2.0% regretted having had a tubal sterilization at 1 year after the procedure and 2.7% did so after 2 years. Using a multivariate analysis to identify risk factors for regret, we found that almost all characteristics were more closely associated with regret at 1 year than at 2 years postoperatively. Of the characteristics we examined that could be objectively determined preoperatively, we considered only age less than 30 years and (for whites) a concurrent cesarean section to be risk factors for regret at 2 years after sterilization. However, in absolute terms, less than 10% of women with both those risk factors regretted having the procedure.

Safety of abortion and tubal sterilization performed separately versus concurrently

Concurrent abortion and sterilization are preferred by many women to avoid a second hospitalization, operation, and, in some instances, general anesthesia. Several authors have shown concern, however, that the two procedures carry a higher risk of morbidity when performed concurrently versus separately. To determine whether the concurrent performance of sterilization and induced abortion is as safe as the two procedures performed separately, we selected women undergoing these procedures from two separate multicenter, prospective, national United States studies: the Joint Program for the Study of Abortion and the Collaborative Review of Sterilization. Using standard definitions of major morbidity, we calculated the crude rate of one or more major complications to be 0.9% for the abortion-only group, 1.7% for the group concurrent abortion and tubal sterilization. Thus our data suggest that performing concurrent abortion and sterilization is as safe as performing those procedures separately.

Family history and the risk of breast cancer

To investigate whether a family history of breast cancer increases a woman's risk of developing breast cancer, we analyzed data from the Centers for Disease Control's Cancer and Steroid Hormone Study. The 4,735 cases were women 20 to 54 years old with a first diagnosis of breast cancer ascertained from eight population-based cancer registries; the 4,688 controls were women selected at random from the general population of these eight areas. Compared with women without a family history of breast cancer, women who had an affected first-degree relative had a relative risk of 2.3; women with an affected second-degree relative had a relative risk of 1.5; and women with both an affected mother and sister had a relative risk of 14. The risk of breast cancer for a woman was higher if her first-degree relative had unilateral rather than bilateral breast cancer or had breast cancer detected at a younger rather than older age. For women aged 20 to 39, 40 to 44, and 45 to 54 years, the estimated annual incidence of breast cancer per 100,000 women attributable to a first-degree family history of breast cancer was 51.9, 115.1, and 138.6, respectively, and that attributable to a second-degree family history of breast cancer was 12.1, 19.2, and 92.4, respectively.

Contraceptive use before tubal sterilization

A woman's decision to undergo tubal sterilization may be affected by her experience with temporary contraception. To examine this issue we analyzed data from the Collaborative Review of Sterilization, a multicenter, prospective study of the health effects of sterilization operations on women aged 15-44 years. Data on contraceptive use by a comparison group of nonsterilized women were drawn from a random, population-based sample of women aged 20-44 years who were controls in a large study of cancer and steroid hormone use. Sterilized women reported ever using a higher average number of contraceptive methods than did nonsterilized women. As compared with nonsterilized women, a higher percentage of sterilized women reported ever using contraceptives (99% versus 91%), especially two types, barrier and rhythm or withdrawal. Prior to selecting sterilization as a permanent contraceptive method, the sterilized women had more extensive experience with temporary contraceptives, particularly the less effective ones, than did the comparable nonsterilized women.

Endometrial cancer: how does cigarette smoking influence the risk of women under age 55 years having this tumor?

This analysis of the Cancer and Steroid Hormone Study, a multicenter, population-based case control investigation of hormone use by women of reproductive age and endometrial, breast, and ovarian cancer shows that cigarette smoking is not associated with either an increased or a decreased risk of endometrial cancer. This study included 437 women with endometrial cancer and 3200 control subjects, all of whom were between the ages of 20 and 54 years at the time of interview. The absence of any alteration of the risk of endometrial cancer and smoking was found consistently no matter which variable was used as a measure of smoking--ever or never smoked cigarettes, former or current smoking, light or heavy smoking, or age smoking began.