Asymptomatic hyperglycaemia and major ischaemic heart disease events in Britain.

OBJECTIVE--To examine the association between non-fasting serum glucose concentrations and major ischaemic heart disease (IHD) events (fatal and non-fatal myocardial infarction). DESIGN--A prospective study. SUBJECTS--A population based sample of 7735 middle aged British men. Known diabetics, men with a glucose concentration > or = 11.1 mmol/l at screening, and hypertensive patients taking regular medication were excluded from the analysis. With exclusions (n = 509) and missing glucose values (n = 49), there were 7177 men available for analysis. MAIN OUTCOME MEASURES--Major IHD events (fatal and non-fatal myocardial infarction) during 9.5 years follow up on all men. RESULTS--There were 505 major IHD events, 222 fatal and 283 non-fatal, in the 7177 men studied. There was a non-linear relation between the glucose concentration and the risk (per 1000 men per year) of all major IHD events and fatal IHD events, with the excess risk in the upper quintile of the glucose distribution (> or = 6.1 mmol/l). The unadjusted relative risks (RR) in the upper glucose concentration quintile compared with the first to the fourth quintiles combined were 1.4 (95% CI 1.1, 1.7) for all events and 1.3 (95% CI 1.0, 1.7) for fatal events. Adjustment for age, smoking, occupational status, body mass index, physical activity, systolic blood pressure, total and high density lipoprotein cholesterol, and triglyceride concentrations had a minimal effect on these relative risk estimates. This non-linear relationship between the serum glucose concentration and the risk of a major IHD event was observed in men with no evidence of IHD at screening (n = 5518) but not in men with IHD (n = 1659). In the former group, the RR (adjusted for major coronary risk factors) for all major IHD events in the upper quintile relative to the lower quintiles combined was 1.5 (95% CI 1.2, 2.0) and for fatal IHD events was 1.8 (95% CI 1.1, 2.6). CONCLUSION--These data suggest that asymptomatic hyperglycaemia is an independent risk factor for major IHD events.     

Body mass index and the initial manifestation of coronary heart disease in women aged 40-59 years.

A population-based case-control study was conducted to evaluate body mass as a coronary heart disease (CHD) risk factor among women 40-59 years of age. Cases were women aged 40-59 whose first manifestation of CHD was angina (No. = 133), nonfatal myocardial infarction (No. = 90), and sudden unexpected death (No. = 18) during 1960-1982. Two randomly selected controls were matched on age and time of the initial disease manifestation of the case. The adjusted relative risk for weight and body mass index respectively demonstrated a moderate association with all CHD as well as with angina, but no association with definite CHD (myocardial infarction or sudden unexpected death). To determine if the observed association between body mass index and angina was possibly attributable to differential misclassification bias (i.e. obese women were, in contrast to non-obese women, preferentially labelled as having coronary artery disease) data for angina were stratified by confirmed versus unconfirmed cardiac origin. In the unconfirmed angina analysis, the 75th percentile for weight contrasted with the 25th percentile was associated with a 50% increase in the risk of being labelled as having angina (adjusted odds ratio (OR) = 1.59, 95% confidence interval (CI): 1.11-2.28), while a similar contrast for Quetelet Index was also associated with a nearly 2-fold increase in the risk of being labelled as having angina (adjusted OR = 1.74, 95% CI: 1.18-2.57).(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute myocardial infarction: association with time since stopping smoking in Italy. GISSI-EFRIM Investigators. Gruppo Italiano per lo Studio della Sopravvivenza nell''Infarto. Epidemiologia dei Fattori di Rischio dell''Infarto Miocardico.

STUDY OBJECTIVE--The study aimed to investigate the relationship between years since stopping smoking and the risk of acute myocardial infarction. DESIGN--This was a hospital based, multicentre, case-control study conducted in Italy between September 1988 and June 1989 within the framework of the GISSI-2 clinical trial. SETTING--Over 80 coronary care units in various Italian regions participated. SUBJECTS--A total of 916 incident cases of acute myocardial infarction, below age 75 years, and with no history of ischaemic heart disease, and 1106 control subjects admitted to the same hospitals for acute, non-neoplastic, cardiovascular or cerebrovascular conditions that were not known or suspected to be related to cigarette smoking took part in the study. MAIN OUTCOME MEASURES AND RESULTS--Measures were relative risk (RR) estimates of acute myocardial infarction according to the time since stopping smoking and adjusted for identified potential confounding factors. Compared with never smokers, the multivariate RRs were 1.6 (95% confidence interval (CI) 0.8,3.2) for subjects who had given up smoking for one year; 1.4 (95% CI 0.9,2.1) for those who had stopped for two to five years; 1.2 (95% CI 0.7,2.1) for six to 10 years; and 1.1 (95% CI 0.8,1.8) for those who had not smoked for over 10 years. The estimated RR for current smokers was 2.9 (95% CI 2.2,3.9). The risks of quitters were higher for heavier smokers and those below age 50 years, while no difference emerged in relation to the duration of smoking, sex, and other risk factors for myocardial infarction. CONCLUSIONS--These results indicate that there is already a substantial drop in the risk of acute myocardial infarction one year after stopping. The risk in ex-smokers, however, seemed higher (although not significantly) than that of those who had never smoked, even more than 10 years after quitting. This could support the existence of at least two mechanisms linking cigarette smoking with acute myocardial infarction--one involving thrombogenesis or spasms that occurs over the short term, and another involving atherosclerosis that is a long term effect.     

Prospective study of selenium levels in toenails and risk of coronary heart disease in men

Selenium is a trace mineral that plays a role in antioxidant defenses as a component of glutathione peroxidase. Epidemiologic findings on the relation of selenium status to risk of heart disease are inconsistent. Therefore, the authors investigated prospectively the association between toenail selenium levels and risk of coronary heart disease (CHD) in a case-control study nested within the Health Professionals Follow-up Study. Between 1987 and 1992, 470 CHD cases were newly diagnosed. A control matched to each case on age, smoking status, and date of toenail return was chosen. Toenail selenium levels analyzed by neutron activation were not associated with risk of total CHD after adjustment for age and smoking and other CHD risk factors (highest quintile vs. lowest: odds ratio (OR) = 0.86, 95% confidence interval (CI): 0.55, 1.32; p-trend = 0.75). Selenium level was inversely associated with risk of nonfatal myocardial infarction for extreme quintiles (OR = 0.54, 95% CI: 0.31, 0.93; p-trend = 0.07), was less so for fatal CHD (OR = 0.79, 95% CI: 0.39, 1.60; p-trend = 0.61), and was directly associated with coronary revascularization procedures (OR = 2.38, 95% CI: 1.11, 5.09; p-trend = 0.02). Although these findings suggest no overall relation between selenium status and CHD, a specific protective role for myocardial infarction cannot be excluded.     

Weight and mortality in Finnish women

Mortality in relation to body mass index (BMI) was studied in 17,159 healthy Finnish women aged 25-79 followed up for a median of 12 years. Mortality from all cases was related to BMI only in non-smokers aged 25-64, among whom the mortality pattern was "U"-shaped, with a minimum in the second quintile of BMI (the reference range), and about 1.5 times higher in quintiles I and V. Most of the excess risk of mortality among overweight women was due to cardiovascular diseases. During the first 7 years of follow-up, and high risk (relative risk (RR) = 1.7, 95% confidence interval (CI) = 1.0-2.9 for quintile V compared to quintile II) depended on the association of BMI with the initial blood pressure level, but in the later years, the relative risk of cardiovascular death, ranging from 1.6 (95% CI = 1.0-2.5) for women in quintile III up to 2.6 (95% Ci = 1.7-4.0) for those in quintile V, was largely independent of the baseline levels of the main biological risk factors. The excess mortality among thin women under the age of 65 was mainly due to non-cardiovascular diseases (RR = 1.7, 95% CI = 1.2-2.3 for quintile I compared to quintile II) and was not attributable to antecedent disease, smoking or the biological risk factors studied. Among women aged 65 and over, overall mortality varied little with BMI, but thinness seemed to predict deaths from cancers (RR = 1.6, 95% CI = 0.9-3.0).(ABSTRACT TRUNCATED AT 250 WORDS)     

Risk factors for premature myocardial infarction: a matched case-control study

Background: Myocardial infarction in young age is increasing. Identifying risk factors could be important for health promotion. We studied classic atherosclerotic risk factors in premature myocardial infarction. Methods: In this matched case-control study, which was conducted from 2005 to 2007 in Birjand County, the east of Iran, atherosclerotic risk factors (hyperten-sion, family history of coronary artery diseases, obesity, diabetes mellitus, dyslipidemia) of 98 patients affected by acute myocardial infarction aged under 50 years were compared with that of 98 healthy neighborhood controls. Results: Mean levels of cholesterol, triglyceride, low-density lipoprotein, as well as systolic blood pressure and body mass index were significantly higher in cases than in controls. There was a positive association between coronary artery disease at younger age and dyslipidemia OR=2.8 [95% CI: 1.5, 5.2], smoking OR=6.4 [95% CI: 3.0, 13.5], systolic hypertension OR=3.1 [95% CI: 1.5, 6.3], family history of coronary artery diseases OR=10.9 [95% CI: 3.2, 37.9] and diabetes OR=2.5 [95% CI: 1.04, 6.2]. Conclusion: Smoking, systolic hypertension and dyslipidemia were the most common risk factors among patients with premature myocardial infarction.     

Psychosocial factors at work and myocardial infarction among men in Kaunas, Lithuania

OBJECTIVES: The association between job demand and job control and first nonfatal myocardial infarction was studied among the 25- to 64-year-old male population in Kaunas, Lithuania. METHODS: A translation of the Swedish version of the demand-control questionnaire was used. Both psychosocial work characteristics as independent risk factors and the possible effects of traditional risk factors (smoking, arterial hypertension, overweight) were analyzed in a case-control study among 203 men diagnosed in 2001-2002 with a first nonfatal myocardial infarction (cases) and 287 men randomly selected as controls. A logistic regression analysis was used to estimate the odds ratio for developing myocardial infarction in relation to self-reported job demand and job control. Possible confounders (age, marital status, education, type of occupation, smoking, blood pressure, body mass index) were controlled. RESULTS: The adjusted odds ratio was 0.56 [95% confidence interval (95% CI 0.37-0.85)] and 1.53 (95% CI 1.04-2.38), for demand and control, respectively. That for workers with low demand and low control was 1.89 (95% CI 0.99-3.60) as compared with low demand and high control. The risk of myocardial infarction for men in passive jobs (low demand and low control) was twofold that of the other respondents. CONCLUSIONS: The association between low job control and the risk of myocardial infarction was found to be consistent with research in western populations. In contradiction, however, to findings in western studies, low demand, rather than high demand proved to be a risk factor for 25- to 64-year-old men. Employees in passive jobs had the highest risk.     

The relationship between fat distribution and some chronic diseases in 11,825 women participating in the DOM-project

The prevalence of reported chronic diseases was studied in quintiles of waist/hip ratio and Quetelet index in 11,825 women aged 40-73 presenting for mammographic screening in the DOM-project. After adjustment for age and Quetelet index, increased waist/hip ratio was found to be associated with an increased prevalence of diabetes mellitus, hypertension, cholecystectomy and a lower prevalence of varicose veins. No associations were observed between waist/hip ratio and the prevalence of angina pectoris, gout and rheumatism. The odds ratios, adjusted for age and Quetelet index, of the highest versus the lowest quintile of waist/hip ratio were 3.4 (95% CI 1.4-8.3) for diabetes mellitus; 2.2 (95% CI 1.7-2.8) for hypertension; 2.0 (95% CI 1.2-3.4) for cholecystectomy, and 0.81 (95% CI 0.68-0.95) for varicose veins. After adjustment for waist/hip ratio and age, Quetelet index was found to be associated with an increased prevalence of hypertension, cholecystectomy and varicose veins. Quetelet index, however, was not found to be related to diabetes, gout or rheumatism. We conclude that in a representative sample of Dutch women older than 40 years, fat distribution in addition to overweight is related to important chronic diseases.     

Shiftwork and myocardial infarction: a case-control study

OBJECTIVES: Previous studies have indicated an association between shiftwork and coronary heart disease. The increased risk could be due to job strain, which could act as a mediator of disease. There is also a possibility that interaction between shiftwork and job strain could occur that may induce or modify the development of disease. We conducted this study to explore the relation between shiftwork, job strain, and myocardial infarction. METHODS: 2006 cases with acute first time myocardial infarction were compared with 2642 controls without symptoms of myocardial infarction, and obtained from the same population that gave rise to the cases (population based case-control study). RESULTS: Myocardial infarction risk was associated with shiftwork both in men (odds ratio (OR) 1.3, 95% confidence interval (95% CI) 1.1 to 1.6) and women (OR 1.3, 95% CI 0.9 to 1.8). In the age group 45-55, the relative risk was 1.6 in men and 3.0 in women. The results cannot be explained by job strain, age, job education level, or smoking. No interaction was found between shiftwork and job strain. CONCLUSIONS: The findings indicate that shiftwork is associated with myocardial infarction in both men and women. The mechanism is unclear, but the relation cannot be explained by job strain, smoking, or job education level.

 

     

Reproductive factors and risk of myocardial infarction.

The relation of reproductive factors to risk of myocardial infarction in women aged 45-69 years was examined in a case-control interview study carried out in Massachusetts from 1986 to 1990. Each of 858 cases of first myocardial infarction was age-matched with a control from the same precinct of residence. Conditional logistic regression was used to control the matching factors and the major known and suspected risk factors for coronary heart disease. For parous women compared with nulliparous women, the estimated relative risk of myocardial infarction was 1.8 (95% confidence interval (CI) 1.0-3.3). Among parous women, the relative risk estimate for five or more births relative to fewer births was 1.4 (95% CI 1.0-2.0); the estimate for a first birth before age 20 relative to a later age at first birth was 1.7 (95% CI 1.1-2.6). The greatest increase in risk was observed for women who had both an early age at first birth and five or more children. However, confounding by factors related to socioeconomic status may have contributed to the results. Compared with women who had a natural menopause at age 50 or older, women who reached the menopause before age 45 were at increased risk regardless of type of menopause: The estimated relative risks were 2.1 (95% CI 1.3-3.2), 1.7 (95% CI 1.0-2.7), and 1.7 (95% CI 1.0-2.8) for early natural menopause, bilateral oophorectomy, and hysterectomy with retention of one or both ovaries, respectively. These results suggest that early cessation of ovulatory function, whether due to natural causes or to surgery, increases the risk of myocardial infarction. Age at menarche was not related to myocardial infarction risk.     

Beta-carotene intake and risk of nonfatal acute myocardial infarction in women

There are indications that beta-carotene, but not pre-formed vitamin A, is protective on the risk of acute myocardial infarction (AMI). The relationship between nonfatal AMI and the intake of beta-carotene and retinol was investigated in a case-control study conducted between 1983 and 1992 in northern Italy on 433 women with nonfatal AMI and 869 controls in hospital for acute, non-cardiovascular, non-neoplastic, non-digestive, non-hormone related conditions. Odds ratios (OR), with their 95% confidence intervals (CI), were computed by unconditional multiple logistic regression analysis, including terms for age, education, body mass index, smoking, alcohol and coffee drinking, menopausal status, hormone replacement therapy and history of diabetes, hypertension and hyperlipidemia. The risk of AMI was inversely related to beta-carotene intake, with an OR of 0.5 (95% CI: 0.3 to 0.8) for the highest quintile of intake compared to the lowest (² trend = 10.53, p < 0.01). Retinol intake was not associated with AMI, with an OR of 0.9 (95% CI: 0.6 to 1.3) for the highest quintile of intake compared to the lowest. Analysis in separate strata of covariates indicated that the inverse association of beta-carotene intake with risk of AMI was appreciably stronger in younger, lean women with no history of diabetes or hypertension, and in current smokers. The results of this study indicate that the risk of nonfatal AMI in women is inversely related to intake of beta-carotene containing foods, but not foods containing retinol.     

Whole-grain and fiber intakes and periodontitis risk in men

BACKGROUND: Diabetes and hyperglycemia increase periodontitis risk, severity, and extent. Increased whole-grain and fiber intakes are associated with improved insulin sensitivity and may therefore affect periodontitis risk. OBJECTIVE: The objective was to examine the associations between whole-grain and fiber intakes and periodontitis risk. DESIGN: We prospectively followed 34,160 male US health professionals aged 40-75 y at the outset. We updated medical and lifestyle information biennially with questionnaires and diet every 4 y by using a validated food-frequency questionnaire. We excluded men reporting periodontitis, myocardial infarction, stroke, and hypercholesterolemia before 1986 and those with incomplete dietary data. All diabetics were excluded. Periodontitis was determined by a report of professionally diagnosed disease and validated by a diagnosis of periodontitis by a periodontist from a blinded review of radiographs. RESULTS: Men in the highest quintile of whole-grain intake were 23% less likely to get periodontitis than were those in the lowest quintile (multivariate RR: 0.77; 95% CI: 0.66, 0.89; P for trend < 0.001) after adjustment for age, smoking, body mass index, alcohol intake, physical activity, and total energy intake. Periodontitis was not associated with refined-grain intake (multivariate RR comparing extreme quintiles of intake: 1.04; 95% CI: 0.89, 1.23; P for trend = 0.37). Cereal fiber was inversely related to periodontitis risk (multivariate RR comparing extreme quintiles of intake: 0.85; 95% CI: 0.73, 0.99; P for trend = 0.03), but the association was not significant after adjustment for whole-grain intake. CONCLUSION: Increasing whole grain in the diet without increasing total energy intake may reduce periodontitis risk.     

Association of serum uric acid with all-cause and cardiovascular disease mortality and incident myocardial infarction in the MONICA Augsburg cohort. World Health Organization Monitoring Trends and Determinants in Cardiovascular Diseases.

Because previous findings have been inconsistent, we explored the association of serum concentrations of uric acid with all-cause and cardiovascular disease mortality and myocardial infarction prospectively. We used data from 1,044 men who are members of the World Health Organization Monitoring Trends and Determinants in Cardiovascular Diseases (MONICA) Augsburg cohort. The men, 45-64 years of age in 1984-1985, were followed through 1992. There were 90 deaths, 44 of which were related to cardiovascular disease; 60 men developed incident nonfatal or fatal myocardial infarction. We estimated hazard rate ratios from Cox proportional hazard models. Uric acid levels > or =373 micromol/liter (fourth quartile) vs < or =319 micromol/liter (first and second quartile) independently predicted all-cause mortality [hazard rate ratio = 2.8; 95% confidence interval (CI) = 1.6-5.0] after adjustment for alcohol, total cholesterol/high-density lipoprotein cholesterol ratio, hypertension, use of diuretic drugs, smoking, body mass index, and education. The adjusted risk of cardiovascular disease mortality was 2.2 (95% CI = 1.0-4.8), and that of myocardial infarction was 1.7 (95% CI = 0.8-3.3). Although residual confounding cannot be excluded, our results are among the few, in men, demonstrating a strong positive association of elevated serum uric acid with all-cause mortality. Future investigations may be able to evaluate whether uric acid contributes independently to the development of cardiovascular disease or is simply a component of the atherogenic metabolic condition known as the insulin resistance syndrome.     

Decreased blood selenium and risk of myocardial infarction

The relationship between whole blood selenium levels and risk of acute myocardial infarction was investigated in a community-based control study in Auckland, New Zealand. A pilot study in 14 patients admitted to hospital within 4 hours of onset of symptoms demonstrated that selenium levels were stable in the first 16 hours after admission for an acute myocardial infarction. Some 252 cases (199 men, 53 women) presenting to hospital within 20 hours of onset of acute myocardial infarction were compared with 838 controls (500 men, 338 women), group-matched for age and sex. Myocardial infarction patients had significantly lower mean selenium levels: 82.8 and 87.9 micrograms/l in male cases and controls (p = 0.003) and 82.1 and 88.5 micrograms/l in female cases and controls (p = 0.02) respectively. The relative risks of myocardial infarction in participants with selenium levels below the median level (85 micrograms/l) in comparison with participants above the median were 1.6 (95% CL 1.1-2.2) and 1.7 (95% CL 0.9-3.5) in men and women respectively. The effects of a low selenium level on risk of myocardial infarction were confined to cigarette smokers. These results suggest the hypothesis that a decreased blood selenium in the presence of cigarette smoking is a risk factor for coronary heart disease.     

Maternal smoking during pregnancy and childhood obesity

A recent cohort study suggested that maternal smoking during pregnancy might be a risk factor for childhood obesity. Data from the obligatory school entry health examination in six Bavarian (Germany) public health offices in 1999-2000 were used to assess the relation between maternal smoking during pregnancy and childhood obesity (n = 6,483 German children aged 5.00-6.99 years). A body mass index greater than the 90th percentile was defined as overweight, and a body mass index greater than the 97th percentile was defined as obesity. The main exposure was maternal smoking during pregnancy. The prevalences of overweight and obesity, expressed as percentages, increased in the following order: never smoked (overweight: 8.1, 95% confidence interval (CI): 7.2, 9.0; obesity: 2.2, 95% CI: 1.7, 2.7); less than 10 cigarettes daily (overweight: 14.1, 95% CI: 11.1, 17.7; obesity: 5.7, 95% CI: 3.7, 8.2); and 10 or more cigarettes daily (overweight: 17.0, 95% CI: 10.1, 26.2; obesity: 8.5, 95% CI: 3.7, 16.1). The adjusted odds ratios for maternal smoking during pregnancy were 1.43 (95% CI: 1.07, 1.90) for overweight and 2.06 (95% CI: 1.31, 3.23) for obesity. A dose-dependent association between overweight/obesity and maternal smoking during pregnancy was observed that could not be explained by a wide range of confounders, suggesting that intrauterine exposure to inhaled smoke products rather than lifestyle factors associated with maternal smoking accounts for this finding.     

Overweight and stroke in the Whitehall study.

STUDY OBJECTIVE--The aim was to examine the risk of increasing overweight for death from stroke. DESIGN--This was a prospective cohort study, in which the main outcome measure was the mortality ratio for stroke with increasing body mass index. SETTING--Civil service departments, Whitehall, London. SUBJECTS--Participants were 17,753 men aged 40 to 64 years. MEASUREMENTS AND MAIN RESULTS--208 stroke deaths were recorded. Men aged 40 to 54 in the most overweight quintile of body mass index had a mortality ratio of 2.01 (95% confidence interval 0.9 to 4.7) compared to the thinnest quintile. The mortality ratio was 1.19 (95% CI 0.7 to 2.0) in men aged 55 to 64. The increase in risk was more apparent in non-smokers: age adjusted mortality ratio 2.58 (95% CI 1.2 to 5.7). When smoking status and overweight were considered in combination a gradient of the age adjusted mortality ratio was observed, from 1.0 in thinner/non-smokers up to 3.15 in fatter/current smokers. On the assumption that smoking and obesity cause strokes, an estimated 60% of strokes could be prevented if these two easily identifiable risk factors could be avoided. CONCLUSIONS--The risks of overweight for death from stroke were more apparent in younger subjects and non-smokers. A substantial proportion of stroke deaths occurring under the age of 80 years would probably be prevented if cigarette smoking and overweight could be avoided.     

Exposure to urban nitrogen dioxide pollution and the risk of myocardial infarction

OBJECTIVES: This study attempted to determine whether long-term exposure to nitrogen dioxide (NO2), an indicator of motor vehicle exhaust, increases the risk of myocardial infarction (MI). METHODS: A population-based case-control study was conducted among men aged 25-64 years and residing in Kaunas, Lithuania. The study included all cases of first-time myocardial infarction in 1997-2000. Interviews with patients treated in hospitals elicited information on smoking and other risk factors, including residential histories. A high response rate (77.4%) resulted in 448 cases and 1777 controls. Nitrogen dioxide (NO2) was selected for analysis as an indicator of traffic-related air pollution. The annual air pollution levels were estimated for the residential districts; thereafter the data were linked to the home addresses of the cases and controls. RESULTS: After adjustment for age, education, smoking, blood pressure, body mass index, marital status, and psychological stress, the risk of myocardial infarction was higher for the men exposed to medium [odds ratio (OR) 1.43, 95% confidence interval (95% CI) 1.04-1.96] and high (OR 1.43, 95% CI 1.07-1.92) NO2 levels. The data suggested a stronger association among 55- to 64-year-old men. The risk of myocardial infarction increased by 17% among the 25- to 64-year-old men (OR 1.17, 95% CI 1.01-1.35) and by 34% among those aged 55-64 years (OR 1.34, 95% CI 1.08-1.67) from the first to the third tertile of NO2 exposure. CONCLUSIONS: The results indicate that urban NO2 pollution may increase the risk of myocardial infarction and that vehicle emissions may be of particular importance.     

Relation between obesity and breast cancer in young women

This study was conducted to assess the relation between body size and risk of breast cancer among young women. A case-control study was conducted among women aged 21-45 years living in three counties in Washington State. Cases were women born after 1944 with invasive or in situ breast cancer that was diagnosed between January 1, 1983, and April 30, 1990. Controls were selected using random digit dialing and were frequency-matched to cases on the basis of age and county of residence. Interviews took place between 1986 and 1992. Body size was evaluated using indices from several different time periods. After adjustment for confounders, a decreased risk of breast cancer was found for women in the highest quintile of body mass index (weight (kg)/height (m)2) as compared with the lowest quintile (for maximum lifetime body mass index, odds ratio = 0.69, 95% confidence interval (CI) 0.51-0.94). Age modified the relation between body size and risk of breast cancer. The odds ratio for women in the highest quintile of maximum body mass index who were aged 21-35 years was 0.29 (95% CI 0.16-0.55), as compared with an odds ratio of 1.5 for women aged 36-45 years (95% CI 0.9-2.5) (p for interaction = 0.003). This study supports prior research showing a decreased risk of breast cancer associated with increased body size among premenopausal or young women. More detailed analysis in this study found a strong effect that was limited to the youngest age group (< or = 35 years).     

Hormone replacement therapy and the risk of myocardial infarction in women with coronary risk factors

To assess the risk of myocardial infarction in users of post-menopausal hormone replacement therapy who are at high risk of coronary disease because of hypertension, diabetes mellitus, or smoking, we used data from a previously published case-control study of women 45-74 years. After adjustment for age, ethnicity, and education, the odds ratio for myocardial infarction in current users of hormone replacement therapy was 0.9 (95% confidence interval (CI) = 0.5-1.6) in women with no major coronary risk factors, 0.8 (95% CI = 0.5-1.8) in women with one risk factor, and 1.1 (95% CI = 0.5-2.2) in women with two risk factors.     

Swedish moist snuff and myocardial infarction among men

BACKGROUND: Previous studies have provided inconsistent results on possible increased risk of cardiovascular disease with the use of smokeless tobacco. The aim of this study was to assess whether long-term use of Swedish moist snuff (widely used among Swedish men) increases the risk of acute myocardial infarction. METHODS: This case-control study was conducted in 2 Swedish counties. We identified 1760 men, age 45-70 years, who had a myocardial infarction in 1992-1994. We randomly selected male controls from the study base after stratification for age and hospital catchment area. Information about snuff consumption, smoking history, hypertension, and other factors was obtained by mailed questionnaire and medical examination. The participation rate was 77% among cases and 78% among controls, with tobacco use data available for 1432 cases and 1810 controls. RESULTS: After adjustment for age, hospital catchment area, and smoking, the relative risk of first acute myocardial infarction was 1.1 (95% confidence interval=0.8-1.5) for former snuff users and 1.0 (0.8-1.3) for current snuff users. Analyses limited to either nonfatal or fatal cases did not change the results. Among the controls, the consumption of smokeless tobacco was strongly associated with certain risk factors for myocardial infarction such as smoking, hypertension, and high body mass index. CONCLUSION: The hypothesis that smokeless tobacco increases the risk for myocardial infarction is not supported in the present study.