Breast cancer and oral contraceptive use: a case-control study

The effect of oral contraceptive (OC) use was examined among parous breast cancer cases diagnosed at less than or equal to 45 years of age, and in two different general population control groups of parous women. The primary analysis compared 278 cases with 520 controls. In the secondary analysis, a subgroup of 190 cases were compared with 190 controls from another reference group. In both analyses, ever use of OC, duration of OC use, and OC use prior to first pregnancy showed no significant association with breast cancer risk. Also in both analyses, in women with prior benign breast disease OC use increased the risk of breast cancer, although this finding was statistically significant only in the larger group used in the primary analysis.

Interactions between benign breast disease and other risk factors for breast cancer

A population-based incident case-control study of breast cancer in Northern Alberta, Canada, provided an opportunity to evaluate interactions between the occurrence of benign breast disease (BBD) and other potential risk factors. Overall there was a 2-fold excess risk of breast cancer among women with BBD. This excess persisted regardless of the number of years from first biopsy for BBD to diagnosis of breast cancer, suggesting a permanent alternation in risk with BBD. Significant variations of the BBD--breast cancer association were noted with several factors. The excess risk of breast cancer among women with BBD was enhanced by having a later age at menarche, a later age at first birth, or lower parity. The usual protective effect of late age at menarche was seen only among women without BBD, and was supplanted by a 4-fold elevated risk among women with BBD. The deleterious effects of later age at first birth and nulliparity were greater among women with BBD. These patterns generally support the notion that hormonal factors mediate the relation between BBD and the development of breast cancer.

Variation in frequency of natural reinfection with influenza A viruses

To investigate the frequency of natural reinfection with influenza A viruses, 55 children followed from birth along with the 44 other children and 85 adults in their families were observed for varying periods between 1975 and 1981 in the Houston Family Study. Persons infected in 1976 or early 1977 with influenza A subtype H3N2 experienced a high rate of reinfection during the 1977-78 season (63% in one group of young children) and additional reinfections in 1980-81. Persons in whom H3N2 infection was first observed in 1977-78 had little or no reinfection in 1980-81; one reinfection was observed in 1980-81 among 19 young children at risk. Only one reinfection with influenza A subtype H1N1 was observed following introduction of the virus in early 1978 despite exposure in 1978-80 and a substantial outbreak in 1980-81. Statistically significant protection from reinfection in young children followed from birth was not noted for the 1977-78 H3N2 outbreak but was present in 1979-81 for both H3N2 and H1N1 viruses. Reasons for variations in reinfection suggested by this data include 1) socioeconomic and other factors influencing intensity of exposure, 2) age at primary infection, 3) varying degrees of antigenic difference between sequential variants of a major subtype, and 4) unrecognized immunogenicity or virulence differences between subtypes and variants.

Differentiation of Clostridium difficile toxin from Clostridium botulinum toxin by the mouse lethality test

The mouse lethality test is the most sensitive method for confirming the diagnosis of infant botulism. Both Clostridium difficile and Clostridium botulinum produce heat-labile toxins which are lethal for mice and can be found in the feces of infants. These two toxins can be distinguished from one another in this assay when both are present in the same fecal specimen because they appear to be immunologically distinct toxins.

IgM and IgG antibody response in two immunosuppressed patients with Legionnaires' disease. Evidence of reactivation of latent infection

Two patients in whom pneumonia due to Legionella pneumophila developed while they were receiving immunosuppressive therapy had serologic evidence of prior infection with the same serogroup of L. pneumophila two and eight months prior to their clinical pneumonia. This suggests that the pneumonia in these patients may have been due to the reactivation of a latent infection, possibly due to their immunosuppressed state. A new enzyme-linked immunosorbent assay (ELISA) was developed to detect IgG and IgM antibodies to L. pneumophila, and the kinetics of these antibody responses were useful diagnostically.

Factors influencing participation in a rubella vaccination program

During the course of a 7-day voluntary rubella vaccination program conducted at a large community-teaching hospital, 718 hospital workers were vaccinated, an overall vaccination rate of 29%. During and after the vaccination campaign, physicians, employees, and students were surveyed as to their reasons for accepting or rejecting rubella vaccine. Prior to the campaign few hospital workers realized that rubella vaccination was of importance in their case. Although paycheck notices, newsletters, and poster displays were all effective in publicizing the campaign, hospital workers most frequently cited discussions with other workers as the major factor leading to their acceptance of vaccination. The belief that a history of rubella, diagnosed clinically, was adequate assurance of immunity was common among physicians and employees and was the major obstacle to greater success in the campaign. Vaccine reactions were infrequent and mild and did not lead to excessive employee absenteeism.

Cerebrovascular disease type specific mortality: 1968-1977

Death certificates for the period 1968-1977 were examined to determine the trend, in the United States, of cerebrovascular disease death rates by type of event and demographic subgroup. The largest declines were for hemorrhagic strokes and among nonwhites. The number of hemorrhagic stroke deaths declined by 45 percent and th age-adjusted rate declined by 53 percent. Similar figures for nonwhites were 18 percent and 36 percent, respectively. It was surprising to note that the number of cerebrovascular deaths reported as poorly defined rose by 17 percent. Data on hypertension were examined. The possibility that the results with respect to hypertension are artifactual indicates the need for clinical studies which will examine the relationship between hypertension and cerebrovascular disease mortality.

Age at menarche, urine estrogens and breast cancer risk

In 511 nulliparous women aged 15-19 years and 347 aged 30-39, an analysis has been undertaken of the relationship of urine concentrations of the three principal estrogens to age, age at menarche and Quetelet's index of adiposity. The analysis was undertaken by means of multiple regression, controlling for each of the 12 centers from which the data originated, as well as for the other study variables. In the younger women, age was strongly and positively related to concentrations of E1 and E2 and less so to E3. In the age group 30-39, follicular phase specimens showed positive relationships with age for all three fractions but luteal specimens did not. Age at menarche showed inverse relationships to levels of E1 and E2 which were significant in the younger but not in the older age group. The associations of estrogens with Quetelet's index were weak and not statistically significant. The data suggest that women whose menarche occurs early not only have a longer duration of exposure to estrogens during years which are probably important in the initiation of breast cancer but, in addition, their exposures are at a higher level during those years and probably at later ages also. These observations support the hypothesis that the mechanism of the association of early menarche with breast cancer risk is via the association of both with estrogen stimulus.

Blood pressure and haemodynamics in teenagers

It has been suggested that a hyperkinetic circulatory state, with high cardiac output, causes high blood pressure in childhood and, secondarily, in adulthood. We studied blood pressure and cardiac output in 319 subjects aged 15 to 19. Blood pressure was measured with an automated device; cardiac output was estimated by M-mode echocardiography and indexed by body surface area. The distribution of cardiac output was stratified using quartiles. Mean arterial pressure was virtually constant over these strata, with boys and girls showing essentially the same pattern. Linear regression of mean arterial pressure on cardiac output yielded a coefficient which was not significantly different from zero. A history of high blood pressure in the parents was positively associated with mean arterial pressure, but unrelated to cardiac output, in the offspring. This evidence does not support the hypothesis that the hyperkinetic circulatory state causes high blood pressure in childhood; rather, raised blood pressure in adolescents appears to relate to increased peripheral vascular resistance. Therefore, our findings lend support to the view that change in blood pressure over time is caused by a gradual increase in peripheral resistance beginning early in life.

Dietary sodium and arterial pressure: problems of studies within a single population

The nature of the relationship between dietary sodium and arterial pressure remains uncertain, largely because of the difficulty of investigating this relationship within a single population. There are two main hypotheses: one requires that hypertensive and normotensive patients differ in their sodium intake, the other that they differ in their susceptibility to dietary sodium. Neither hypothesis has been fully explored. In this paper the types of study required to test each hypothesis are considered and published work is used to illustrate the problems of interpreting studies in this field.

Parity and breast cancer: confirmed evidence of an effect on age at diagnosis

An evaluation is made of the hypothesis of Woods et al. (1) that the number of full-term pregnancies constitutes a factor of growth acceleration in breast cancer. Our results confirm, at least in part, the effect of parity on age at diagnosis of breast cancer. Patients with two or more children were significantly younger at the time of diagnosis than were those with none or one child. Age at first birth and duration of lactation do not seem to be, in this analysis, confounding factors for the observed association.

The comparative epidemiology of benign breast lumps and breast cancer in Western Australia

Totals of 313 patients with breast cancer and 1,283 patients biopsied for benign breast lumps were found in Western Australia in 1978 through review of all histopathological, hospital and cancer registry records. The incidence of breast cancer rose to 146.9 per 100,000 at age 45-54 years and thereafter increased little. The biopsy rate for benign breast lumps rose more sharply to 420.2 per 100,000 at age 45-54 years and then fell. This pattern was mainly due to benign mammary dysplasia (BMD); fibroadenoma showed an earlier peak biopsy rate (30-34 years) and other (mainly non-neoplastic) benign lumps were biopsied at a relatively constant rate throughout adult life. Rates of breast cancer, BMD and fibroadenoma showed similar relationships to the other descriptive variables studied. The rates of each were higher in single than married women, in residents of the Perth area than residents of other parts of the State and in women employed in professional and related occupations than other employed women. They were lower in migrants from Europe (excluding Great Britain) than native-born Australians and in women of low socio-economic status than women of high status. Not all these differences were statistically significant. Rates of other breast lumps did not generally vary in these ways and were conversely related to country of birth, area of residence and socio-economic status. The parallels in descriptive epidemiology between breast cancer, BMD and fibroadenoma suggest that they may share aetiological factors.

Occupational exposure and 12-year spirometric changes among Paris area workers

A follow-up study over 12 years was conducted among 556 men aged 30 to 54 in 1960 and working at that time in factories around Paris (France). Various occupational exposures were recorded at the time of the 1960 survey after a technical study of each workplace. The annual rate of decline of FEV1 during 12 years was estimated for each subject from the measurements in 1960 and 1972. This rate (the FEV1 slope) was related independently of FEV1 level (which reflects the loss since the beginning of adult life) and of smoking habits to occupational exposure to dust, gases, and heat. FEV1 slope was significantly related to inhalation of mineral dust (even in the absence of silica) as well as to grain dust, and the slope was steeper with increased intensity of exposure to dust. Analysis of job changes showed that among heavily exposed subjects, those who changed jobs had a less steep slope than those who did not. Our results support the hypothesis of a causal role of exposure to dust in the development of chronic airflow obstruction and of a benefit when exposure to dust ceases. Exposure to dust, gas, and heat usually occurred together so data on gas and heat were analysed after taking account of exposure to dust. The influence of heat on FEV1 decline showed a clear trend. Results suggest that exposure to gases associated with exposure to dust or heat or both had a deleterious effect. After adjusting for age, smoking, and FEV1 level (ASLA) the following average slopes were obtained: 44 ml/a (for exposure to none or to only a slight amount of dust, or to gases alone), 51 ml/a (heat), 53 ml/a (noticeable dust), 55 ml/a (noticeable dust and heat), 60 ml/a (noticeable dust, heat, and high concentration of gases). Independently of the occupational exposures, ASLA FEV1 slopes among manual workers were related to skill, being 44 ml/a for skilled and 51 ml/a for unskilled men. Independently of social class and occupational exposures recorded, there were differences in FEV1 slopes by factory, suggesting that one should not rely on using one factory as the control of studies of occupational exposure to another.

Quality of breast-cancer care in Italian general hospitals

The diagnostic and therapeutic care and degree of follow-up delivered to 2406 breast-cancer patients over two years (1978-79) in 31 Italian hospitals are reviewed. Although there was broad agreement about recommended treatment protocols, staging by standard methods was recorded in only 44% of patients, assessment and reporting of side-effects was considered in only 49% of all treated patients, follow-up data at two years were available for only 54% of living patients, and the dropout rate from chemotherapy protocols was 35%. Improvement of these unsatisfactory aspects of care would allow a better appreciation of the real benefit that could be achieved with recommended protocols and would result in a more effective use of health resources.

Risk, susceptibility and the epidemiology of proliferative neoplastic disease: descriptive vs. mechanistic approaches

Recently there has been a confusing and somewhat frustrating difference of opinion in epidemiology concerning the relative merit and utility of descriptive versus mechanistic knowledge in approaching the comprehension and control of human cancer. This distinction has both historical and evolutionary rationale; it generally being necessary to know something of WHAT is happening before one can be legitimately concerned with HOW it is happening. As outlined below, however, there is little justification for making value judgements based on this distinction, and the situation is more one in which descriptive approaches and mechanistic approaches are equally essential in the development of a systematic viewpoint, a viewpoint providing guidance to meaningful intervention.

Differences in trends of postneonatal mortality by birthweight in upstate New York, 1968-1979

Postneonatal mortality among neonatal survivors and the distribution of age at death among infant deaths were examined for births occurring in upstate New York, 1968-1979. Postneonatal mortality rates increased among infants weighing 501-1500 grams. Infants weighing 1501-2000 grams experienced an increase in postneonatal mortality during the mid-1970s, later returning to the level of 1968. Among infants 2001+ grams, postneonatal mortality declined throughout the study period. Among all levels of birthweight, the proportion of infant deaths occurring as postneonatal deaths increased.

Type 2 (non-insulin-dependent) diabetes--an epidemiological overview

Despite the use of a wide range of different methodologies and diagnostic criteria, epidemiological studies have shown that Type 2 (non-insulin-dependent) diabetes has a global distribution and its prevalence varies from country to country, in different ethnic groups in the same country, and between the same ethnic group undergoing internal or external migration. Rural-urban and migration studies indicate that change towards a 'Westernized' lifestyle is associated with a dramatic increase in the prevalence rates for Type 2 diabetes. Between populations, comparisons are confounded by a wide range of different ascertainment rates, survey methodologies, and diagnostic criteria for diabetes. However, low prevalence rates for Type 2 diabetes are seen in Eskimos and populations of the Far East, while the highest are seen in American Indians, urbanized Pacific Island populations, and migrant Asian Indians. Available evidence suggests that these latter groups have a genetic susceptibility to Type 2 diabetes ('diabetes genotype') and that the disease is unmasked by environmental factors. There appears to be a spectrum of interaction between genetic and environmental factors--in certain populations the genetic role may be more important than environmental, or vice versa. Epidemiological studies, apart from their value in population screenings and case-finding, have contributed to the new classification and diagnostic criteria for diabetes and our understanding of risk factors and host characteristics in the aetiology of Type 2 diabetes.

Caffeine consumption and benign breast disease: a case-control comparison

In this case-control comparison of 323 women with benign breast disease and 1,458 controls, no differences were noted in the coffee and tea consumption patterns of the cases and controls. These findings do not support the recent suggestion of Minton, et al, that methylxanthine ingestion is causally related to benign breast disease or breast cancer.

Effect of age at first childbirth on risk of developing specific histologic subtype of breast cancer

Epidemiologic variables related to breast cancer risk were assessed in a case-control study of 332 women with breast carcinoma and 1353 comparison women. Risk factors for breast cancer as a whole included nulliparity, late age at first childbirth, early age at menarche, late age at menopause, personal history of benign breast disease, family history of breast cancer, and among postmenopausal women, body weight. These risk factors were then analyzed with respect to histologic subtype of breast cancer involved, i.e., duct-derived or lobular tumors, to determine whether the association between any of the risk factors and breast cancer varied according to histopathologic subtype. Histologic subtype for the 316 cases reviewed included 284 duct cancers and 32 lobular carcinomas. Although slight differences were noted among some of the risk factors and the variety of cancer, none of the differences was marked except for the variable age at birth birth. For ductal carcinoma, the risk was highest among nulliparous women and decreased the younger a woman was at the time she gave birth to her first child. The risk of infiltrating lobular carcinoma, however, was lowest among nulliparous females or those who had given birth at a young age and increased the older a woman was when she gave birth to her first child.

An evaluation of risk factors for stroke in a Dutch community

The objective of the present epidemiological study was to reevaluate the relationship of various suspect risk factors to stroke within a Dutch community. The Tilburg study lends support to findings in other countries concerning the greater stroke risk of persons with high blood pressure, heart disorders, and diabetes mellitus. Significant interactions of both age and a history of myocardial infarction with hypertension on stroke risk were noted. The presence of overweight and possible transient ischemic attacks (TIA) were found related to stroke onset. No increase in stroke risk was associated with cigarette smoking. The extent of leisure time physical activity during one's lifetime was found inversely related to one's chances for stroke.

Interferon independence of genetically controlled resistance to flaviviruses

Flavivirus-resistant C3H/RV mice injected with sheep anti-interferon globulin and then infected with either West Nile or yellow fever virus survived and displayed no disease symptoms. Also, treatment of embryo fibroblast cultures prepared from C3H/RV or congenic susceptible C3H/HE mice with anti-interferon serum resulted in an increased yield of West Nile virus from both types of cultures, but the amount of infectious virus produced by resistant cultures remained 1 to 1.5 logs lower than that produced by susceptible cell cultures. These results indicate that the mode of expression of the flavivirus resistance gene differs significantly from that of the Mx gene conferring resistance to influenza virus-induced disease in A2G mice.

Protective role of human milk against sudden death from infant botulism

We examined the possibility that human milk and formula milk might differentially affect the severity of the infant botulism because they differ in immunologic composition and in influence on the normal intestinal microflora against which Clostridium botulinum must compete. A beneficial effect of human milk was suggested by the different feeding experiences of the moderate, hospitalized patients and the sudden death cases. Of patients hospitalized in California, 66% (33/50) were still being nursed at onset of illness, a percentage significantly greater than that of matched controls (P less than 0.01). In contrast, all ten California cases of sudden infant death attributable to C. botulinum infection were being fed iron-supplemented formula milk at death) unlike their controls, P less than 0.02) and had received no human milk within ten weeks of death. A beneficial effect of human milk was also observed in differences in mean age at onset; hospitalized breast-fed patients were almost twice as old (13.8 +/- 6.7 weeks) as were hospitalized formula-fed patients (7.6 +/- 2.9 weeks) (P less than 0.01). Human milk (or possibly other factors associated with breast-feeding) appeared to have moderated the severity at onset of infant botulism, allowing time for hospital admission, whereas for some infants with this illness, formula milk (or possibly other factors associated with formula feeding) was linked to sudden unexpected death.

Occupational risk for laryngeal cancer

In a case-control analysis, we studied the effects of type of employment on laryngeal cancer risk using the interview data from the Third National Cancer Survey. Effects were measured relative to the risk for those employed in a group of arbitrarily defined industries and occupations with low risk. We excluded females and controlled for age, tobacco use, alcohol use, and race in the analysis. We found ratio estimates above 3.0 for workers in the railroad industry and the lumber industry; and for sheetmetal workers, grinding wheel operators, and automobile mechanics.

Legal abortion: the public health record

The increasing availability and utilization of legal abortion in the United States has several important effects on public health in the 1970's. It reduced deaths and surgical complications among women of childbearing age; it made possible the development of safer surgical procedures for pregnancy termination; and it increased the provision of low-cost outpatient gynecologic services. There is some concern about potential adverse outcomes in future desired pregnancies and possibly higher risks of breast cancer in certain women.

Adult T-cell lymphoma-leukaemia in Blacks from the West Indies

Six Black patients (five born in the West Indies and one in Guyana), aged 21-55 years, had adult T-cell lymphoma-leukaemia diagnosed in the U.K. This disorder is rare in Europe and the U.S.A., but is more common in Japan. Five patients had severe hypercalcaemia which correlated with disease activity, although osteolytic lesions were found in only one. Other clinical features were lymphadenopathy and a high white blood-cell count (range 27-67 X 10(9)/l) with a predominance of pleomorphic lymphoid cells with pronounced nuclear irregularities prominent at ultrastructural level. The cells in all cases formed rosettes with sheep red blood-cells and lacked terminal transferase. Analysis with OKT monoclonal antibodies in four cases confirmed a mature T-cell phenotype defined as helper/inducer (T4+, T6-, T8-) in three. Combination chemotherapy resulted in short-lived remissions; four patients died and two have survived 3-6 months. The disease in these patients is indistinguishable on clinical and pathological grounds from adult T-cell leukaemia/lymphoma in Japan. Geographical clustering among certain racial groups suggests common aetiological factors in the pathogenesis of this disease. The finding of high titre antibody against the structural core protein (p24) of a new human C-type leukaemia virus (human T-cell leukaemia/lymphoma virus) in all tested cases from this series and data from all but one case from Japan suggest that one such factor may be viral.

Adolescent health in Alameda County

A cross-sectional study of 194 adolescents in Alameda County, California, was performed to investigate health care behavior, personal adjustment, substance abuse, and medical and dental morbidity. A multivariate analysis of this sample using age, sex, ethnic group, and family type as independent variables was carried out. Females were less likely than males to have a regular place for medical care, and youths belonging to single parent families were less likely than those from intact families. Older adolescents, blacks and Hispanics used hospitals and clinics more frequently, while whites used private physicians more frequently than did other ethnic groups. Also blacks and Hispanics were less likely to have received recent dental care than whites. Levels of substance abuse were comparable to national levels, and increased significantly with age. Though overall medical morbidity was low, the study confirms previous findings of significant levels of dental decay particularly in black youth. A significant relation exists between less dental care and dental decay, though no such relation exists between medical care and medical morbidity. The study has potential implications for better preventive approaches to adolescent health care.

[Blood pressure, renin angiotensin aldosterone system and other cardiovascular risk factors in children of essential hypertensives (author's transl)]

In the present study, blood pressure, the renin angiotensin aldosterone system, and other cardiovascular risk factors, such as glucose, cholesterine, and triglycerides, were investigated in 294 offspring of essential hypertensives (5-34 years) and in 122 children of normotensive parents (5-34 years). Offspring of essential hypertensives showed statistically significant higher systolic and diastolic blood pressure values than those of normotensive parents (p less than 0.003, less than 0.005, respectively). Furthermore, in children of hypertensive parents a statistically significant higher body weight and body mass index than in controls could be observed (p less than 0.006, less than 0.001, respectively). With the exception of statistically significant, lower mean supine plasma aldosterone values (p less than 0.02) in children of hypertensive parents, no major differences between the two groups were seen in stimulated aldosterone, supine and stimulated plasma renin activity, and plasma cortisol. Furthermore, in the present study, 41 hypertensive parents, 65 (normotensive) spouses of hypertensives, and 47 (normotensive) parents of control children were investigated. As expected, hypertensive parents showed statistically significant higher blood pressure values than parents of control children and their spouses (p less than 0.001). Interestingly, hypertensive parents had not only a higher body mass index than control parents but also than their spouses (p less than 0.01 and less than 0.02, respectively). These findings support a genetic disposition as being the underlying cause of higher body weight in hypertensives and make it less probable that a higher food intake in hypertensive families is responsible for this phenomenon. The results of the present study indicate that early body weight control in children of hypertensive parents may be an important contribution to the prevention of hypertension.

Age at menarche, probability of ovulation and breast cancer risk

An analysis is undertaken of the frequency of ovulation in 17 groups of women aged 15 to 19 who had been the subjects of other studies. A urine specimen of at least 8 h accumulation had been provided on the 20th or 21st day of a menstrual cycle by 681 women. Analysis is restricted to 431 specimens which had been collected between 11 and 3 days prior to the onset of the subsequent menstrual period. A pregnanediol concentration of less than 1 mg per litre in such a specimen was taken as evidence that the cycle was anovular. The probability of a cycle being anovular was inversely and significantly related to the number of years since menarche, and, with years since menarche held constant, was positively but not significantly associated with age at menarche. This observation indicates that women with early menarche do not have a longer duration of exposure to anovular cycles than do those whose menarche is delayed, and that variation in the duration of exposure to post-menarcheal anovular cycles does not explain the association of breast cancer risk with early age at menarche. The 17 groups of women were classified into four categories according to ethnic origin and breast cancer incidence in the populations from which they derived. Anovular cycles were not more common in the high-risk groups; indeed, the two centers in the lowest risk category had the highest proportion of anovular cycles.

Serum concentrations of total and non-protein-bound oestradiol in patients with breast cancer and in normal controls

In premenopausal women with breast cancer, total serum oestradiol (E2) concentrations are normal but nonprotein-bound E2 concentration are significantly raised. This is not due to low sex-hormone-binding-globulin (SHBG) binding capacities which are within the normal range and is unlikely to be due to the small but significant decrease in albumin concentrations. In post-menopausal patients, both total and non-protein-bound E2 are significantly raised: this may be explained partially by lower SHBG binding capacities. In patients and controls there is a highly significant correlation between non-protein-bound E2 and SHBG but, for a given SHBG binding capacity, the patients have more non-bound E2 than controls. It is concluded that the breast in women with breast cancer may be exposed to elevated levels of biologically active E2 although the reasons for this remain obscure.