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Biomedical subjects

A Ascherio

Publications and source records attributed to A Ascherio.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hepatitis B vaccination and the risk of multiple sclerosis.

BACKGROUND: Reports of multiple sclerosis developing after hepatitis B vaccination have led to the concern that this vaccine might be a cause of multiple sclerosis in previously healthy subjects. METHODS: We conducted a nested case-control study in two large cohorts of nurses in the United States, those in the Nurses' Health Study (which has followed 121,700 women since 1976) and those in the Nurses' Health Study II (which has followed 116,671 women since 1989). For each woman with multiple sclerosis, we selected as controls five healthy women and one woman with breast cancer. Information about hepatitis B vaccination was obtained by means of a mailed questionnaire and was confirmed by means of vaccination certificates. The analyses included 192 women with multiple sclerosis and 645 matched controls and were conducted with the use of conditional logistic regression. RESULTS: The multivariate relative risk of multiple sclerosis associated with exposure to the hepatitis B vaccine at any time before the onset of the disease was 0.9 (95 percent confidence interval, 0.5 to 1.6). The relative risk associated with hepatitis B vaccination within two years before the onset of the disease was 0.7 (95 percent confidence interval, 0.3 to 1.8). The results were similar in analyses restricted to women with multiple sclerosis that began after the introduction of the recombinant hepatitis B vaccine. There was also no association between the number of doses of vaccine received and the risk of multiple sclerosis. CONCLUSIONS: These results indicate no association between hepatitis B vaccination and the development of multiple sclerosis.

Case-Control Studies↗
PubMed2001

Blood donations and risk of coronary heart disease in men.

BACKGROUND: In experimental animals, iron overload appears to promote atherosclerosis and ischemic myocardial damage, but the results of epidemiological studies that relate iron stores to risk of coronary heart disease (CHD) have been inconsistent. METHODS AND RESULTS: We prospectively studied blood donations, which effectively reduce body iron stores, in relation to the risk of CHD among participants in the Health Professionals Follow-up Study. The lifetime history of blood donation was assessed with a questionnaire in 1992. The 38 244 men who were free of diagnosed cardiovascular disease at that time were included in the analyses. During 4 years of follow-up, we documented 328 nonfatal myocardial infarctions and 131 coronary deaths. Although the number of lifetime blood donations was strongly associated with lower plasma ferritin levels in a subsample, the blood donation was not associated with risk of myocardial infarction or fatal CHD. The age-adjusted relative risk (RR) of myocardial infarction for men in the highest category of blood donations (>/=30) compared with never donors was 1.2 (95% CI 0. 8 to 1.8), and this RR was not materially changed after adjustment for several coronary risk factors. No significant associations were found between blood donation and the risk of myocardial infarction in analyses restricted to men with hypercholesterolemia or those who never used antioxidant supplements or aspirin. CONCLUSIONS: The study results do not support the hypothesis that reduced body iron stores lower CHD risk.

Adult↗
PubMed2001

Cigarette smoking and the incidence of Parkinson's disease in two prospective studies.

An inverse association between cigarette smoking and idiopathic Parkinson's disease has been reported in several retrospective studies, but prospective evidence is available only for men. We assessed the association between the incidence of Parkinson's disease and smoking in two large prospective cohort studies comprising men and women. New cases of Parkinson's disease were identified in the Nurses' Health Study for 1976-1996, and in the Health Professionals Follow-up Study for 1986-1996. Smoking history was assessed at baseline and updated on subsequent biennial questionnaires. In women, the age-adjusted rate ratios (95% confidence intervals) for Parkinson's disease relative to never-smokers were 0.7 (0.5, 1.0) for past smokers, and 0.4 (0.2, 0.7) for current smokers. In men, the age-adjusted rate ratios for Parkinson's disease relative to never-smokers were 0.5 (0.4, 0.7) for past smokers, and 0.3 (0.1, 0.8) for current smokers. In both cohorts, the strength of the association decreased with time since quitting (among past smokers), increased with number of cigarettes per day (among current smokers), and increased with pack-years of smoking. These prospective findings confirm that an inverse association between smoking and the incidence of Parkinson's disease exists in both men and women.

Adult↗
PubMed2001

Prospective study of caffeine consumption and risk of Parkinson's disease in men and women.

Results of case-control studies and of a prospective investigation in men suggest that consumption of coffee could protect against the risk of Parkinson's disease, but the active constituent is not clear. To address the hypothesis that caffeine is protective against Parkinson's disease, we examined the relationship of coffee and caffeine consumption to the risk of this disease among participants in two ongoing cohorts, the Health Professionals' Follow-Up Study (HPFS) and the Nurses' Health Study (NHS). The study population comprised 47,351 men and 88,565 women who were free of Parkinson's disease, stroke, or cancer at baseline. A comprehensive life style and dietary questionnaire was completed by the participants at baseline and updated every two to four years. During the follow-up (10 years in men, 16 years in women), we documented a total of 288 incident cases of Parkinson's disease. Among men, after adjustment for age and smoking, the relative risk of Parkinson's disease was 0.42 (95% CI: 0.23-0.78; p for trend < 0.001) for men in the top one-fifth of caffeine intake compared to those in the bottom one-fifth. An inverse association was also observed with consumption of coffee (p for trend = 0.004), caffeine from noncoffee sources (p for trend < 0.001), and tea (p for trend = 0.02) but not decaffeinated coffee. Among women, the relationship between caffeine or coffee intake and risk of Parkinson's disease was U-shaped, with the lowest risk observed at moderate intakes (1-3 cups of coffee/day, or the third quintile of caffeine consumption). These results support a possible protective effect of moderate doses of caffeine on risk of Parkinson's disease.

Adult↗
PubMed2001

Population-based study of alpha- and gamma-tocopherol in plasma and adipose tissue as biomarkers of intake in Costa Rican adults.

BACKGROUND: gamma-Tocopherol is the most abundant form of vitamin E in the US diet, but alpha-tocopherol concentrations are the highest in plasma and tissues. Although plasma and adipose tissue concentrations of alpha-tocopherol have been used as biomarkers of intake, the relation between gamma-tocopherol intake and concentrations in plasma and adipose tissue is unknown. OBJECTIVE: Our goal was to investigate in a randomly selected population from Costa Rica whether plasma or adipose tissue concentrations of alpha- and gamma-tocopherol are suitable biomarkers of intake. DESIGN: A total of 361 men (x +/- SD age: 55 +/- 11 y) and 121 women (aged 59 +/- 10 y) completed a 135-item food-frequency questionnaire and provided a fasting blood sample and adipose tissue biopsy sample. RESULTS: Dietary gamma-tocopherol correlated with adipose tissue (r = 0.37, P < 0.001) and plasma (r = 0.42, P < 0.001) concentrations, regardless of supplement use. Dietary alpha-tocopherol correlated poorly with adipose tissue (r = 0.15, P < 0.01) and plasma (r = 0.16, P < 0.001) concentrations, and these correlations were even lower when users of vitamin supplements (n = 24) were excluded (adipose tissue: r = 0.10, P < 0.05; plasma: r = 0.09, P < 0.05). Compared with subjects who reported palm shortening (36%) as the major type of fat used for cooking, subjects using soybean oil (52%) had higher amounts of both alpha- and gamma-tocopherol in their diets. However, only gamma-tocopherol concentrations were higher in the plasma and adipose tissue of soybean oil users. CONCLUSIONS: Plasma and adipose tissue concentrations of gamma-tocopherol are equally good biomarkers of intake. The weak associations between alpha-tocopherol intake and plasma or adipose tissue concentrations suggest that these biomarkers are influenced more by factors other than alpha-tocopherol intake.

Adipose Tissue↗
PubMed2001

Multiple sclerosis and age at infection with common viruses.

Increased risk of multiple sclerosis has been reported among individuals with a history of measles and other common childhood diseases during adolescence, infectious mononucleosis, or exposure to the canine distemper virus. We investigated these associations in a case-control study nested within the Nurses' Health Study (121,700 women traced since 1976) and the Nurses' Health Study II (116,671 women traced since 1989). Age at diagnosis of common viral diseases and birth order were obtained through a questionnaire. Our results include 301 cases with multiple sclerosis and their (up to six) matched controls. Except for infectious mononucleosis, which was a moderate risk factor (odds ratio = 2.1, 95% confidence interval = 1.5-2.9), we found little association between history of common viral diseases or exposure to canine distemper virus and risk of multiple sclerosis. We did find a relation between mumps after 15 years of age (odds ratio = 2.3, 95% confidence interval = 1.2-4.3) or measles after age 15 years of age (odds ratio = 2.8, 95% confidence interval = 0.8-9.1) and multiple sclerosis. Birth order was not materially related to multiple sclerosis. Our findings support the hypothesis that individuals who suffered from infectious mononucleosis, a marker of late infection with the Epstein-Barr virus, have an increased risk of multiple sclerosis. Late infection with other common viruses may also be associated with increased risk.

Adult↗
PubMed2000

Dietary fat in relation to risk of multiple sclerosis among two large cohorts of women.

Ecologic correlations suggest that higher intake of saturated fat and lower intake of polyunsaturated fat might increase the risk of multiple sclerosis (MS), but the results of case-control studies have been inconsistent. Because no prospective data are available, the authors examined these associations in two large cohorts, the Nurses' Health Study, which consisted of 92,422 women with 14 years of follow-up (1980-1994) and the Nurses' Health Study II, which consisted of 95,389 women with 4 years of follow-up (1991-1995). They documented 195 new cases of MS. The pooled multivariate relative risks comparing women in the highest quintile with those in the lowest were 1.1 (95% confidence interval: 0.7, 1.7) for total fat, 0.7 (95% confidence interval: 0.5, 1.2) for animal fat, 1.2 (95% confidence interval: 0.7, 2.1) for vegetable fat, 0.8 (95% confidence interval: 0.5, 1.3) for saturated fat, 1.1 (95% confidence interval: 0.7, 1.7) for monounsaturated fat, 1.7 (95% confidence interval 1.0, 2.8) for n-6 polyunsaturated fat, 1.3 (95% confidence interval: 0.8, 2.0) for trans unsaturated fat, and 0.7 (95% confidence interval: 0.4, 1.1) for cholesterol. Omega-3 fatty acids from fish were also unrelated to risk. However, the authors observed a nonsignificantly lower risk of MS for a higher intake of linolenic acid. These findings do not support relations between intakes of total fat or major specific types of fat and the risk of MS.

Adult↗
PubMed2000

Oral contraceptives and the incidence of multiple sclerosis.

BACKGROUND: Experimental and clinical data suggest a protective effect of estrogens on the development and progression of MS. METHODS: We assessed whether MS incidence was associated with oral contraceptive use or parity in two cohort studies of U.S. women, the Nurses' Health Study (NHS; 121,700 women aged 30 to 55 years at baseline in 1976) and the Nurses' Health Study II (NHS II; 116,671 women aged 25 to 42 years at baseline in 1989). Participants with a diagnosis of MS before baseline were excluded. Oral contraceptive history and parity were assessed at baseline and updated biennially. During follow-ups of 18 years (NHS) and 8 years (NHS II) we documented a total of 315 definite or probable cases of MS. RESULTS: Neither use of oral contraceptives nor parity were significantly associated with the risk of MS. As compared with women who never used oral contraceptives, the age-adjusted relative risk (95% CI) was 1.2 (0.9, 1.5) for past users, and 1.0 (0.6, 1.7) for current users. Similar results were obtained after adjustment for latitude, ancestry, and other potential confounding factors. There was no clear trend of MS risk with either increasing duration of use or time elapsed since last use. Age at first birth was also not associated with the risk of MS. CONCLUSIONS: These prospective results do not support a lasting protective effect of oral contraceptive use or pregnancy on the risk of MS. The decision to use hormonal contraception should not be affected by its effects on the risk of MS.

Adult↗
PubMed2000

Adiposity and mortality in men.

The relation between measures of adiposity and mortality has been a controversial topic. The authors examined prospectively the relation between several measures of adiposity and risks of overall and cause-specific mortality in 39,756 US men aged 40-75 years. During 10 years of follow-up (1986-1996), 1,972 deaths (747 from cancer, 423 from cardiovascular disease, and 802 from other causes) were documented. An elevated risk of death among the leanest men was partly accounted for by excess mortality during early follow-up and high mortality among those with a history of recent weight loss. After exclusion of men with substantial recent weight loss and deaths occurring during the first 4 years of follow-up, overall and cardiovascular disease mortality among men aged <65 years increased linearly with greater body mass index (BMI) (weight (kg)/height (m)2); multivariate relative risks for overall mortality were 1.0 (referent) for a BMI of <23, 1.21 for a BMI of 23-24.9, 1.19 for a BMI of 25-26.9, 1.39 for a BMI of 27-29.9, and 1.97 for a BMI of >30 (test for trend: p< 0.001). Among men aged > or =65 years, there were no significant relations between BMI and overall, cardiovascular disease, or cancer mortality risk. However, waist circumference strongly predicted risk of death from cardiovascular disease among the older men. These findings indicated that the relation between body fat and mortality was influenced by reverse causation and varied by age.

Adipose Tissue↗
PubMed2000

Physical activity and risk of stroke in women.

CONTEXT: Persuasive evidence has demonstrated that increased physical activity is associated with substantial reduction in risk of coronary heart disease. However, the role of physical activity in the prevention of stroke is less well established. OBJECTIVE: To examine the association between physical activity and risk of total stroke and stroke subtypes in women. DESIGN AND SETTING: The Nurses' Health Study, a prospective cohort study of subjects residing in 11 US states. SUBJECTS: A total of 72,488 female nurses aged 40 to 65 years who did not have diagnosed cardiovascular disease or cancer at baseline in 1986 and who completed detailed physical activity questionnaires in 1986, 1988, and 1992. MAIN OUTCOME MEASURE: Incident stroke occurring between baseline and June 1, 1994, compared among quintiles of physical activity level as measured by metabolic equivalent tasks (METs) in hours per week. RESULTS: During 8 years (560,087 person-years) of follow-up, we documented 407 incident cases of stroke (258 ischemic strokes, 67 subarachnoid hemorrhages, 42 intracerebral hemorrhages, and 40 strokes of unknown type). In multivariate analyses controlling for age, body mass index, history of hypertension, and other covariates, increasing physical activity was strongly inversely associated with risk of total stroke. Relative risks (RRs) in the lowest to highest MET quintiles were 1. 00, 0.98, 0.82, 0.74, and 0.66 (P for trend=.005). The inverse gradient was seen primarily for ischemic stroke (RRs across increasing MET quintiles, 1.00, 0.87, 0.83, 0.76, and 0.52; P for trend=.003). Physical activity was not significantly associated with subarachnoid hemorrhage or intracerebral hemorrhage. After multivariate adjustment, walking was associated with reduced risk of total stroke (RRs across increasing walking MET quintiles, 1.00, 0. 76, 0.78, 0.70, and 0.66; P for trend=.01) and ischemic stroke (RRs across increasing walking MET quintiles, 1.00, 0.77, 0.75, 0.69, and 0.60; P for trend=.02). Brisk or striding walking pace was associated with lower risk of total and ischemic stroke compared with average or casual pace. CONCLUSION: These data indicate that physical activity, including moderate-intensity exercise such as walking, is associated with substantial reduction in risk of total and ischemic stroke in a dose-response manner. JAMA. 2000.

Adult↗
PubMed2000

Circumstances of post-neonatal deaths in Ceara, Northeast Brazil: mothers' health care-seeking behaviors during their infants' fatal illness.

Promotion of oral rehydration therapy (ORT) for the treatment of diarrheal diseases and the WHO case management strategy for acute respiratory infections (ARI) have contributed to significant reductions in infant mortality, but these two conditions remain the leading causes of infant deaths in most developing countries. Identification of the factors contributing to these deaths may contribute to reduce infant mortality from preventable causes. To gain insight into the circumstances and maternal and health services factors that may contribute to infant deaths we used a verbal autopsy method to interview mothers of all infants who died during the previous 12 months (June 1995-May 1996) in 11 municipalities in the State of Ceara, Northeast Brazil. Our results revealed that one-third of the deaths occurred in a hospital and two-thirds at home. Almost all the infants who died at home, however, had been examined one or more times by a doctor, and 36% of them had been hospitalized during the disease episode that resulted in death. For most (85%) of these children the causes of death were diarrhea or acute respiratory infection, and it is likely that death could have been averted if appropriate treatment had been initiated promptly. Three major groups of factors that alone or in combination appeared to contribute to most deaths were delays in seeking medical care on behalf of the parents, medical interventions reported as ineffective by mothers and delays in providing medical care to children who arrived at the hospital too late in the day to be scheduled for consultation. Our findings suggest that government efforts to further reduce infant mortality in Ceara should focus on health education interventions that address quality of home care, recognition of signs of severity and danger and importance of seeking timely medical care: and on improving the quality of care provided at community health centers and hospitals. Measures likely to improve infants' chance of survival include: ensuring prompt access to medical consultation for young children brought to health centers or hospitals with potentially life-threatening symptoms related to infections, health education to mothers on the need for continued home care after discharge and to return to the medical care facility if the child does not recover, and that they have access to medicine prescribed by hospital physicians. Further benefits could be obtained by using community health workers, now integrated into the Family Medicine Program (PSF) health teams, to provide health education, supervise home care, refer mothers to health centers and facilitate their access to hospitals.

Attitude to Health↗
PubMed2000

Short stature and hypertension in the city of Rio de Janeiro, Brazil.

OBJECTIVE: Stature is a powerful indicator of poor nutrition early in life in nations where undernutrition is a public health problem. Hypertension in adults has been associated with factors present early in life such as low birth weight. We tested the hypothesis that short stature is associated with hypertension among adults. DESIGN AND SETTING: A household survey of representative adults in Rio de Janeiro city, Brazil was carried out in 1996. SUBJECTS: Blood pressure and anthropometric measures were collected from 2802 adults in their own households. Prevalence estimates and modelling incorporated the sample design and weights. RESULTS: Age-adjusted prevalence of hypertension for both sexes was lower in the third quartile of stature distribution. In women, but not in men, the odds ratio comparing the first quartile of stature with the fourth quartile was statistically significant with an odds ratio of 1.68 (95%CI 1.02-2.76). Adjusting for known risk factors for hypertension such as age, income, smoking, sodium and alcohol intake and race, the association among women, comparing the first with the fourth quartile for stature, was 1.84 (95%CI 1.03-3.30). With further adjustment for residual of weight on height the ratio reduced to 1.76 (95% CI 0.97-3.19, P value of trend = 0.03). Systolic blood pressure showed a U-shaped association with quartiles of stature, mainly among women, with a beta-coefficient significantly lower at the third quartile. CONCLUSIONS: This association of stature with hypertension supports the theory of an important ontogenetic dependence of adult blood pressure, at least among women.

Adult↗
PubMed2000

Prospective study of major dietary patterns and risk of coronary heart disease in men.

BACKGROUND: Previous studies on diet and coronary heart disease (CHD) focused primarily on individual nutrients or foods. OBJECTIVE: We examined whether overall dietary patterns derived from a food-frequency questionnaire (FFQ) predict risk of CHD in men. DESIGN: This was a prospective cohort study of 44875 men aged 40-75 y without diagnosed cardiovascular disease or cancer at baseline in 1986. RESULTS: During 8 y of follow-up, we documented 1089 cases of CHD (nonfatal myocardial infarction and fatal CHD). Using factor analysis, we identified 2 major dietary patterns using dietary data collected through a 131-item FFQ. The first factor, which we labeled the "prudent pattern," was characterized by higher intake of vegetables, fruit, legumes, whole grains, fish, and poultry, whereas the second factor, the "Western pattern," was characterized by higher intake of red meat, processed meat, refined grains, sweets and dessert, French fries, and high-fat dairy products. After adjustment for age and CHD risk factors, the relative risks from the lowest to highest quintiles of the prudent pattern score were 1.0, 0. 87, 0.79, 0.75, and 0.70 (95% CI: 0.56, 0.86; P: for trend = 0.0009). In contrast, the relative risks across increasing quintiles of the Western pattern score were 1.0, 1.21, 1.36, 1.40, and 1.64 (95% CI: 1.24, 2.17; P: for trend < 0.0001). These associations persisted in subgroup analyses according to cigarette smoking, body mass index, and parental history of myocardial infarction. CONCLUSIONS: These data suggest that major dietary patterns derived from the FFQ predict risk of CHD, independent of other lifestyle variables.

Adult↗
PubMed2000

Adherence to the Dietary Guidelines for Americans and risk of major chronic disease in men.

BACKGROUND: The Dietary Guidelines for Americans and the food guide pyramid aim to reduce the risk of major chronic disease in the United States, but data supporting their overall effectiveness are sparse. The healthy eating index (HEI) measures the concordance of dietary patterns with these guidelines. OBJECTIVE: We tested whether a high HEI score (range: 0-100; 100 is best) calculated from a validated food-frequency questionnaire (HEI-f) could predict lower risk of major chronic disease in men. DESIGN: A cohort of US male health professionals without major disease completed detailed questionnaires on food intake and other risk factors for heart disease and cancer in 1986 and repeatedly during the 8-y follow-up. Major chronic disease outcome was defined as incident major cardiovascular disease (stroke or myocardial infarction, n = 1092), cancer (n = 1661), or other non-trauma-related deaths (n = 366). RESULTS: The HEI-f was weakly inversely associated with risk of major chronic disease [comparing highest with lowest quintile of the HEI-f, relative risk (RR) = 0.89; 95% CI: 0.79, 1.00; P: < 0.001 for trend]. The HEI-f was associated with moderately lower risk of cardiovascular disease (RR = 0.72; 95% CI: 0.60, 0.88; P: < 0.001) but was not associated with lower cancer risk. CONCLUSIONS: The HEI-f was only weakly associated with risk of major chronic disease, suggesting that improvements to the HEI may be warranted. Further research on the HEI could have implications for refinements to the Dietary Guidelines for Americans and the food guide pyramid.

Alcohol Drinking↗
PubMed2000

Epstein-Barr virus and multiple sclerosis.

It has been suggested that the Epstein-Barr virus (EBV) plays a role in the etiology of multiple sclerosis (MS), but individual epidemiologic studies have been inconclusive, in part because of the high prevalence of previous infection among individuals without MS. We conducted a systematic review of case-control studies comparing EBV serology in MS patients and controls. Eight published investigations were identified, including a total of 1,005 cases and 1,060 controls. The summary odds ratio of MS comparing EBV seropositive individuals with EBV seronegative individuals was 13.5 (95% CI = 6.3-31.4). The strength and consistency of this association and the high sensitivity and specificity of EBV serology suggest that these results are not readily explained by an aspecific immune activation among MS patients. These findings support a role of EBV in the etiology of MS.

Antibodies, Viral↗
PubMed2000

Frequency of food consumption and lipoprotein serum levels in the population of an urban area, Brazil.

OBJECTIVE: To identify the association between food group consumption frequency and serum lipoprotein levels among adults. METHODS: The observations were made during a cross-sectional survey of a representative sample of men and women over 20 years old living in Cotia county, S. Paulo, Brazil. Data on food frequency consumption, serum lipids, and other covariates were available for 1, 045 adults. Multivariate analyses adjusted by age, gender, body mass index, waist-to-hip ratio, educational level, family income, physical activity, smoking, and alcohol consumption were performed. RESULTS: Consumption of processed meat, chicken, red meat, eggs and dairy foods were each positively and significantly correlated with LDL-C, whereas the intake of vegetables and fruits showed an inverse correlation. Daily consumption of processed meat, chicken, red meat, eggs, and dairy foods were associated with 16.6 mg/dl, 14.5 mg/dl, 11.1 mg/dl, 5.8 mg/dl, and 4.6 mg/dl increase in blood LDL-C, respectively. Increases of daily consumption of fruit and vegetables were associated with 5.2 mg/dl and 5.5 mg/dl decreases in LDL-C, respectively. Alcohol beverage consumption showed a significant positive correlation with HDL-C. CONCLUSIONS: Dietary habits in the study population seem to contribute substantially to the variation in blood LDL and HDL concentrations. Substantially CHD risk reduction could be achieved with dietary changes.

Adult↗