Biomedical subjects

M J Stampfer

Publications and source records attributed to M J Stampfer.

At least 343 records · Page 19Linked to original sources

PubMed1993

Folate, methionine, and alcohol intake and risk of colorectal adenoma.

BACKGROUND: Reduced methylation of DNA may contribute to loss of the normal controls on proto-oncogene expression. In humans, hypomethylation of DNA has been observed in colorectal cancers and in their adenomatous polyp precursors. Accumulation of DNA methylation abnormalities, observed during progression of human colorectal neoplasia, may be influenced by certain dietary factors. The apparent protective effect of fresh fruits and vegetables, the major folate sources, on colorectal cancer incidence suggests that a methyl-deficient diet contributes to occurrence of this malignancy. Low dietary folate and methionine and high intake of alcohol may reduce levels of S-adenosylmethionine, which is required for DNA methylation. PURPOSE: To determine if dietary factors that may influence methyl availability are related to colorectal adenomas, we prospectively examined the association of folate, methionine, and alcohol intakes and risk of colorectal adenoma. METHODS: We assessed dietary intake for a 1-year period for women of the Nurses' Health Study, started in 1976, and for men of the Health Professionals Follow-up Study, started in 1986--using a semiquantitative food frequency questionnaire. Adenomatous polyps of the left colon or rectum were diagnosed in 564 of 15,984 women who had had an endoscopy between 1980 and 1990 and in 331 of 9490 men who had undergone an endoscopy between 1986 and 1990. RESULTS: High dietary folate was inversely associated with risk of colorectal adenoma in women (multivariate relative risk [RR] = 0.66; 95% confidence interval [CI] = 0.46-0.95 between high and low quintiles of intake) and in men (RR = 0.63; 95% CI = 0.41-0.98) after adjusting for age, family history, indications for endoscopy, history of previous endoscopy, total energy intake, saturated fat intake, dietary fiber, and body mass index. Relative to nondrinkers, drinkers of more than 30 g of alcohol daily (about two drinks) had an elevated risk of adenoma (in women, RR = 1.84, 95% CI = 1.19-2.86; in men, RR = 1.64, 95% CI = 0.92-2.93). Methionine intake was inversely associated with risk of adenomas 1 cm or larger (RR = 0.62; 95% CI = 0.46-0.85, combining men and women). CONCLUSIONS: Folate, alcohol, and methionine could influence methyl group availability, and a methyl-deficient diet may be linked to early stages of colorectal neoplasia. A dietary pattern that increases methyl availability could reduce incidence of colorectal cancer. IMPLICATIONS: These data support efforts to increase dietary folate in segments of the population having diets with low intakes of this nutrient.

Adenoma↗

PubMed1993

Vitamin E consumption and the risk of coronary disease in women.

BACKGROUND: Interest in the antioxidant vitamin E as a possible protective nutrient against coronary disease has intensified with the recognition that oxidized low-density lipoprotein may be involved in atherogenesis. METHODS: In 1980, 87,245 female nurses 34 to 59 years of age who were free of diagnosed cardiovascular disease and cancer completed dietary questionnaires that assessed their consumption of a wide range of nutrients, including vitamin E. During follow-up of up to eight years (679,485 person-years) that was 97 percent complete, we documented 552 cases of major coronary disease (437 nonfatal myocardial infarctions and 115 deaths due to coronary disease). RESULTS: As compared with women in the lowest fifth of the cohort with respect to vitamin E intake, those in the top fifth had a relative risk of major coronary disease of 0.66 (95 percent confidence interval, 0.50 to 0.87) after adjustment for age and smoking. Further adjustment for a variety of other coronary risk factors and nutrients, including other antioxidants, had little effect on the results. Most of the variability in intake and reduction in risk was attributable to vitamin E consumed as supplements. Women who took vitamin E supplements for short periods had little apparent benefit, but those who took them for more than two years had a relative risk of major coronary disease of 0.59 (95 percent confidence interval, 0.38 to 0.91) after adjustment for age, smoking status, risk factors for coronary disease, and use of other antioxidant nutrients (including multi-vitamins). CONCLUSIONS: Although these prospective data do not prove a cause-and-effect relation, they suggest that among middle-aged women the use of vitamin E supplements is associated with a reduced risk of coronary heart disease. Randomized trials of vitamin E in the primary and secondary prevention of coronary disease are being conducted; public policy recommendations about the widespread use of vitamin E should await the results of these trials.

Adult↗

PubMed1993

Vitamin E consumption and the risk of coronary heart disease in men.

BACKGROUND: The oxidative modification of low-density lipoproteins increases their incorporation into the arterial intima, an essential step in atherogenesis. Although dietary antioxidants, such as vitamin C, carotene, and vitamin E, have been hypothesized to prevent coronary heart disease, prospective epidemiologic data are sparse. METHODS: In 1986, 39,910 U.S. male health professionals 40 to 75 years of age who were free of diagnosed coronary heart disease, diabetes, and hypercholesterolemia completed detailed dietary questionnaires that assessed their usual intake of vitamin C, carotene, and vitamin E in addition to other nutrients. During four years of follow-up, we documented 667 cases of coronary disease. RESULTS: After controlling for age and several coronary risk factors, we observed a lower risk of coronary disease among men with higher intakes of vitamin E (P for trend = 0.003). For men consuming more than 60 IU per day of vitamin E, the multivariate relative risk was 0.64 (95 percent confidence interval, 0.49 to 0.83) as compared with those consuming less than 7.5 IU per day. As compared with men who did not take vitamin E supplements, men who took at least 100 IU per day for at least two years had a multivariate relative risk of coronary disease of 0.63 (95 percent confidence interval, 0.47 to 0.84). Carotene intake was not associated with a lower risk of coronary disease among those who had never smoked, but it was inversely associated with the risk among current smokers (relative risk, 0.30; 95 percent confidence interval, 0.11 to 0.82) and former smokers (relative risk, 0.60; 95 percent confidence interval, 0.38 to 0.94). In contrast, a high intake of vitamin C was not associated with a lower risk of coronary disease. CONCLUSIONS: These data do not prove a causal relation, but they provide evidence of an association between a high intake of vitamin E and a lower risk of coronary heart disease in men. Public policy recommendations with regard to the use of vitamin E supplements should await the results of additional studies.

Adult↗

PubMed1993

Fatty acid composition of the subcutaneous adipose tissue and risk of proliferative benign breast disease and breast cancer.

BACKGROUND: Studies in animals and geographic correlations across populations suggest that fatty acid intake may have a positive relationship with breast cancer risk, but analytic epidemiologic studies of fat intake have been less supportive. Adipose tissue analysis provides a more objective assessment of intakes of fatty acids that are not endogenously synthesized than do the questionnaire survey methods used in many epidemiologic studies. PURPOSE: This case-control study of postmenopausal women was designed to examine the relationship between fatty acid composition of subcutaneous adipose tissue and risk of breast cancer and proliferative benign breast disease. In addition, we examined specific hypotheses that breast cancer risk is negatively associated with long-chain N-3 fatty acid intake, positively associated with trans fatty acid intake, and positively associated with increased intake of polyunsaturated fat together with low intake of antioxidants. METHODS: Aspirates of subcutaneous fat from the buttocks were obtained from 380 women with newly diagnosed stage I or II breast cancer and 176 with proliferative benign breast disease. A total of 397 women who were evaluated for breast abnormalities at the same institutions but did not require breast biopsy or whose biopsy revealed nonproliferative benign breast disease served as the control group. We examined associations between saturated, monounsaturated, polyunsaturated, trans, or long-chain N-3 fatty acids and breast cancer, atypical hyperplasia, or proliferative benign breast disease without atypia. RESULTS: We observed no consistent patterns of association between breast cancer risk and any of the categories of fatty acids or the individual constituent fatty acids in the adipose tissue. Saturated fatty acids were inversely associated with risk of proliferative benign breast disease without atypia but not with atypical hyperplasia or breast cancer. This association was not observed, however, when total fat intake was taken into account. Women with high levels of polyunsaturated fatty acids in adipose tissue and low serum or dietary levels of antioxidants were not observed to be at higher risk of breast cancer. CONCLUSIONS: Using an objective measure of intake, we observed no major associations between polyunsaturated fatty acids, including long-chain N-3 fatty acids and trans fatty acids, and risk of breast cancer or proliferative benign breast disease. IMPLICATIONS: These data do not support the hypothesis that intake of specific fatty acids, particularly polyunsaturated and trans fatty acids, is an important risk factor for malignant or benign breast disease.

Adipose Tissue↗

PubMed1993

Endogenous tissue-type plasminogen activator and risk of myocardial infarction.

Endogenous tissue-type plasminogen activator (tPA) has been hypothesised to be a marker of baseline fibrinolytic capacity. We therefore tested whether tPA antigen is associated with the occurrence of future myocardial infarction (MI) among apparently healthy individuals. tPA antigen concentrations were measured at baseline in plasma samples from 231 apparently healthy men from the Physicians' Health Study cohort who later developed MI, and in an equal number of controls matched for age and smoking habit who remained free of reported cardiovascular disease during a follow-up of 60.2 months. In crude matched-pair analyses, baseline concentrations of tPA antigen were higher in cases than controls (p = 0.03) and strongly associated with risk of future MI. Specifically, the relative risks of developing a first MI from lowest (referent) to highest quintiles of tPA antigen were 1.00, 1.27, 1.75, 1.88, and 2.81 (p for trend 0.0008, 95% CI for the relative risk in the fifth as compared with first quintile 1.47 to 5.37, p = 0.002). Analyses which adjusted for risk factors that affect progression of atherosclerosis, particularly HDL-cholesterol, abolished the statistical significance of this association, a finding which suggests that elevations of tPA antigen are a result rather than a cause of atherosclerotic coronary disease. These prospective data suggest that endogenous tPA concentrations increase as a consequence of important preclinical atherosclerosis and therefore may be a marker for risk of future MI.

Adult↗

PubMed1993

A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones.

BACKGROUND: A high dietary calcium intake is strongly suspected of increasing the risk of kidney stones. However, a high intake of calcium can reduce the urinary excretion of oxalate, which is thought to lower the risk. The concept that a higher dietary calcium intake increases the risk of kidney stones therefore requires examination. METHODS: We conducted a prospective study of the relation between dietary calcium intake and the risk of symptomatic kidney stones in a cohort of 45,619 men, 40 to 75 years of age, who had no history of kidney stones. Dietary calcium was measured by means of a semiquantitative food-frequency questionnaire in 1986. During four years of follow-up, 505 cases of kidney stones were documented. RESULTS: After adjustment for age, dietary calcium intake was inversely associated with the risk of kidney stones; the relative risk of kidney stones for men in the highest as compared with the lowest quintile group for calcium intake was 0.56 (95 percent confidence interval, 0.43 to 0.73; P for trend, < 0.001). This reduction in risk decreased only slightly (relative risk, 0.66; 95 percent confidence interval, 0.49 to 0.90) after further adjustment for other potential risk factors, including alcohol consumption and dietary intake of animal protein, potassium, and fluid. Intake of animal protein was directly associated with the risk of stone formation (relative risk for men with the highest intake as compared with those with the lowest, 1.33; 95 percent confidence interval, 1.00 to 1.77); potassium intake (relative risk, 0.49; 95 percent confidence interval, 0.35 to 0.68) and fluid intake (relative risk, 0.71; 95 percent confidence interval, 0.52 to 0.97) were inversely related to the risk of kidney stones. CONCLUSIONS: A high dietary calcium intake decreases the risk of symptomatic kidney stones.

Adult↗

PubMed1993

Intake of trans fatty acids and risk of coronary heart disease among women.

Trans isomers of fatty acids, formed by the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, increase the ratio of plasma low-density-lipoprotein to high-density-lipoprotein cholesterol, so it is possible that they adversely influence risk of coronary heart disease (CHD). To investigate this possibility, we studied dietary data from participants in the Nurses' Health Study. We calculated intake of trans fatty acids from dietary questionnaires completed by 85,095 women without diagnosed CHD, stroke, diabetes, or hypercholesterolaemia in 1980. During 8 years of follow-up, there were 431 cases of new CHD (non-fatal myocardial infarction or death from CHD). After adjustment for age and total energy intake, intake of trans isomers was directly related to risk of CHD (relative risk for highest vs lowest quintile 1.50 [95% Cl 1.12-2.00], p for trend = 0.001). Additional control for established CHD risk factors, multivitamin use, and intakes of saturated fat, monounsaturated fat, and linoleic acid, dietary cholesterol, vitamins E or C, carotene, or fibre did not change the relative risk substantially. The association was stronger for the 69,181 women whose margarine consumption over the previous 10 years had been stable (1.67 [1.05-2.66], p for trend = 0.002). Intakes of foods that are major sources of trans isomers (margarine, cookies [biscuits], cake, and white bread) were each significantly associated with higher risks of CHD. These findings support the hypothesis that consumption of partially hydrogenated vegetable oils may contribute to occurrence of CHD.

Age Factors↗

PubMed1993

A comparison of prospective and retrospective assessments of diet in the study of breast cancer.

Fat intake was examined in relation to risk of breast cancer using dietary questionnaires administered both before and after the diagnosis of breast cancer. Among the Nurses' Health Study cohort members who completed a food frequency questionnaire and were free of cancer in 1986, 398 were diagnosed with breast cancer during 2 years of follow-up. These cases and 798 age-matched controls (cohort members who also completed a dietary questionnaire in 1986 but did not develop breast cancer) were sent another food frequency questionnaire in 1989 inquiring about their diet in 1985. Three hundred cases and 602 controls responded to the second questionnaire. The age-adjusted analysis using the prospective (1986) questionnaire demonstrated no appreciable associations between breast cancer incidence and intakes of total fat (odds ratio (OR) between highest and lowest quintiles = 0.87; 95% confidence interval (CI) 0.54-1.40) and saturated fat (OR = 0.97; CI 0.64-1.46). The age-adjusted analysis using the retrospective (1989) questionnaire suggested positive associations between breast cancer incidence and intakes of total fat (OR = 1.43; 95% CI 0.90-2.27) and saturated fat (OR = 1.38; 95% CI 0.89-2.13). When nutrients were adjusted for total energy intake, the direction and magnitude of the differences between the prospective and retrospective analyses were similar to the analyses unadjusted for energy intake. These results suggest that case-control studies of diet and breast cancer may yield biased associations between fat intake and the risk of breast cancer.

Adult↗

PubMed1993

A prospective cohort study of vasectomy and prostate cancer in US men.

OBJECTIVE: To examine prospectively the relationship between vasectomy and prostate cancer. DESIGN: Cohort study. SETTING: Health professionals (dentists, veterinarians, osteopaths, optometrists, pharmacists, and podiastrists) in the United States. PARTICIPANTS: There were 10,055 male members of the Health Professionals Follow-up Study, aged 40 to 75 years, who had had a vasectomy, and 37,800 members who had not had a vasectomy at the time of study entry in 1986. These participants had provided detailed information on various life-style variables including diet. MAIN OUTCOME MEASURE: Diagnosis of prostate cancer. RESULTS: Between 1986 and 1990, 300 new cases of prostate cancer were diagnosed in participants who were initially free of diagnosed cancer. Vasectomy was associated with an elevated risk of prostate cancer (age-adjusted relative risk, 1.66; 95% confidence interval, 1.25 to 2.21; P = .0004). This elevated risk persisted after excluding 21 stage A1 cases (age-adjusted relative risk, 1.56; 95% confidence interval, 1.15 to 2.11; P = .004). Among men who had their vasectomy at least 22 years in the past (before 1965), the risk of prostate cancer was even higher (relative risk, 1.85; 95% confidence interval, 1.26 to 2.72; P = .002). This elevated risk among men with vasectomy did not appear to be caused by detection bias and persisted when we controlled for diet, level of physical activity, smoking, alcohol consumption, educational level, body mass index, and geographical area of residence. CONCLUSIONS: These results support evidence from other epidemiologic studies that vasectomy increases risk of prostate cancer. The consistency of results among various epidemiologic studies, the increase of risk over time following vasectomy, the apparent lack of confounding or bias, and the existence of physiological changes in the prostate following vasectomy suggest that the association may be causal.

Adult↗

PubMed1993

Smoking cessation and decreased risk of stroke in women.

OBJECTIVE: To prospectively examine the relationship of time since stopping smoking with risk of stroke in middle-aged women. DESIGN: An ongoing prospective cohort of women with 12 years' follow-up data (1976 to 1988), in which information on smoking habits was updated every 2 years by postal questionnaire. POPULATION STUDIED: A total of 117,006 female registered nurses aged 30 to 55 years in 1976 and free of coronary heart disease, stroke, and cancer at baseline. MAIN OUTCOME MEASURES: Incident strokes (fatal and nonfatal), further subdivided into ischemic stroke, subarachnoid hemorrhage, and cerebral hemorrhage. RESULTS: The age-adjusted relative risk of total stroke among current smokers compared with never smokers was 2.58 (95% confidence interval, 2.08 to 3.19). The corresponding relative risk among former smokers was 1.34 (95% confidence interval, 1.04 to 1.73). For total and ischemic stroke, the excess risks among former smokers largely disappeared from 2 to 4 years after cessation. The same patterns of decline were observed regardless of number of cigarettes smoked, the age at starting, or the presence of other risk factors for stroke. CONCLUSIONS: The risk of suffering among cigarette smokers declines soon after cessation and the benefits are independent of the age at starting and the number of cigarettes smoked per day.

Adult↗

PubMed1993

A prospective study of aspirin use and cataract extraction in women.

We examined the association between aspirin use and the rates of cataract extraction during 8 years of follow-up in a large prospective study of women, the Nurses' Health Study. From 1980 to 1988, we documented 448 senile cataracts diagnosed and extracted during 434,680 person-years of follow-up. While we observed a modest positive association at the higher doses of aspirin use in the age-adjusted analyses, no association was found after accounting for other cataract risk factors (relative risk for > or = 20 years of use, 1.08; 95% confidence interval, 0.84 to 1.39). Among women who consumed seven or more tablets per week for 20 or more years, there was no suggestion of protection; if anything, a nonsignificantly elevated risk was observed (relative risk, 1.31; 95% confidence interval, 0.94 to 1.80). We observed no consistent difference in the relationship between aspirin use and cataract when assessed by age. Overall, we found no evidence to support the substantial reduction in risk of cataract among aspirin users as reported in several previous studies.

Age Factors↗

PubMed1993

Recall and selection bias in reporting past alcohol consumption among breast cancer cases.

Recall and selection bias are well-recognized potential problems in case-control studies of alcohol and cancer, but few analyses have attempted to assess the direction and the magnitude of these potential biases. We thus examined alcohol consumption in relation to risk of breast cancer using dietary questionnaires administered both before and after the diagnosis of breast cancer in the Nurses' Health Study (United States). Among cohort members who completed a dietary questionnaire in 1986 and who were free of cancer, 616 were diagnosed with breast cancer during follow-up to December 1989. These cases and 1,277 controls (a random sample of cohort members who did not develop cancer up to 1990) then were sent another questionnaire inquiring about their diet in 1985. Four hundred and ninety-four cases (80.2 percent) and 999 controls (78.2 percent) responded to the second questionnaire. The analysis based on the prospective (1986) questionnaire demonstrated an elevated risk of breast cancer among women who drank 30 or more g of alcohol daily (about two drinks) relative to nondrinkers (odds ratio [OR] = 1.55, 95 percent confidence interval [CI] = 1.01-2.39). The analysis based on the retrospective questionnaire also indicated a similar but slightly attenuated elevation of risk of breast cancer among women who drank at least 30 g daily (OR = 1.42, CI = 0.85-2.40). In these data, bias due to selection and recall had only minor effects on reported intake of alcohol consumption.

Adult↗

PubMed1993

Reproducibility and validity of food intake measurements from a semiquantitative food frequency questionnaire.

Few food frequency questionnaires have been evaluated for their ability to assess intakes of individual foods that may be related to disease independently of their nutrient content. The reproducibility and validity of food intake measurements by a 131-item semiquantitative food frequency questionnaire were evaluated in a sample of 127 men from the Health Professionals Follow-up Study, a large longitudinal study of diet and disease. Each subject completed two questionnaires 1 year apart and two 1-week diet records 6 months apart during the intervening year. Pearson correlations assessing reproducibility between food intakes from the two questionnaires ranged from .31 for pie to .92 for coffee (mean = .59). Validity was measured by comparing food intakes from the second questionnaire with those from the diet records. Pearson correlations corrected for within-person weekly variation in diet record data ranged from .17 for other nuts to .95 for bananas (mean = .63). Large within-person variation precluded the calculation of accurate validity correlations for 29 foods. As we previously observed in women, the foods most often overreported were fruits and vegetables, and meats and dairy products were most often underreported. With few exceptions, reasonable levels of reproducibility and validity were observed for intake of individual foods in this extensive food frequency questionnaire.

Adult↗

PubMed1993

A meta-analysis of cholecystectomy and risk of colorectal cancer.

BACKGROUND: Over 60 studies have addressed the hypothesis that the risk of colorectal cancer is increased following cholecystectomy; these studies have yielded inconsistent findings. The aim of the present study was to quantitatively summarize the results from the collective studies. METHODS: A meta-analysis of the published studies addressing the relation between cholecystectomy and colorectal cancer was conducted. RESULTS: The combined results from 33 case-control studies showed an association between cholecystectomy and risk of colorectal cancer (pooled relative risk [RR] = 1.34; 95% confidence interval [CI] = 1.14-1.57), particularly when limited to the proximal colon (RR = 1.88; 95% CI = 1.54-2.30). In most studies, the risk was stronger when the first 5-15 years following the surgery were excluded. The results from 6 cohort studies, with follow-up to approximately 15 years postcholecystectomy, were generally null (RR = 0.97; 95% CI = 0.82-1.14). A more limited body of evidence suggests that cholelithiasis is related to an elevated risk of proximal colon cancer. CONCLUSIONS: Because the risks varied substantially by study design and because time since cholecystectomy or potentially confounding factors were often not considered, we could not firmly quantitate this risk. However, the findings are consistent with other evidence that suggests some characteristic of bile acid metabolism increases the risk of cancer of the proximal colon.

Case-Control Studies↗

PubMed1993

Hormone replacement therapy and risk of breast cancer: results from epidemiologic studies.

OBJECTIVE: We combined data from published reports of the relation between estrogen use and breast cancer. We specifically addressed the hypothesis that the addition of progestins to estrogen therapy reduces the risk of breast cancer. STUDY DESIGN: A meta-analysis was performed. RESULTS: Replacement hormone therapy is not associated with increased risk of breast cancer in women who have ever used it (relative risk 1.02, 95% confidence interval 0.93 to 1.12). However, current use is associated with increased risk (relative risk 1.40, 95% confidence interval 1.20 to 1.63). Although there was no significant trend with increasing duration of use, women with > or = 10 years of estrogen use had a relative risk of 1.23 (95% confidence interval 1.08 to 1.40). However, data on use of estrogen plus progestins combined from four studies indicate that risk is not reduced and that the overall relative risk is 1.13 (95% confidence interval 0.78 to 1.64). Further, risk did not vary in strata of family history or benign breast disease. CONCLUSION: Although these results exclude a large effect of hormone therapy on risk of breast cancer, we are unable to rule out some risk associated with current or long-term estrogen use.

Breast Neoplasms↗

PubMed1993

The effect of fish oil on blood pressure in mild hypertensive subjects: a randomized crossover trial.

We conducted a double-blind, crossover trial with 18 healthy, untreated mildly hypertensive subjects to test the effect on blood pressure of 6 or 12 g fish oil/d (50% n-3 fatty acids) as compared with an olive oil placebo. Blood pressure was measured every 6 wk in the clinic and three times daily by subjects using a semiautomated device in their homes. Compliance was determined biochemically. No significant changes in home or clinic blood pressure measurements were noted for either dose after 6 or 12 wk of treatment. Clinic blood pressure after 12 g fish oil/d was slightly lower than after placebo treatment by -0.8/-0.4 mm Hg [95% CI: systolic blood pressure (-4.4, +2.8); diastolic blood pressure (-3.2, +2.4)]. Blood pressure changes were not correlated with compliance, baseline dietary fish consumption, or blood pressure. Moderate doses of fish oil did not have a substantial effect on blood pressure. We conclude that fish oil is not a practical treatment for mild hypertension.

Blood Pressure↗

PubMed1993

A 1-y trial of the effect of high-selenium bread on selenium concentrations in blood and toenails.

The concentration of selenium in toenail clippings and blood reflects dietary intake better than does intake calculated from dietary data because of the highly variable selenium concentration in different samples of the same food. However, the time course of selenium intake in relation to subsequent concentrations in toenail clippings is unclear. Therefore, 12 males were fed high-dose (4.91 mumol Se/d), medium-dose (2.61 mumol Se/d), or control (0.41 mumol Se/d) whole-wheat-bread for 1 y and the concentration of selenium was measured in toenail clippings collected every 12 wk for 2 y. Toenail selenium concentration was unaffected by dietary intake in the previous 3 mo and appeared to provide a time-integrated measure of intake over a period of 26-52 wk. Use of selenium concentration in toenail clippings may be an alternative to blood when a measure of long-term average intake is desired. The absence of a short-term effect of diet on toenail selenium concentration also makes this a useful marker of intake in retrospective studies.

Adult↗

PubMed1993

Caffeine and other predictors of bone density among pre- and perimenopausal women.

We evaluated the influence of dietary, anthropomorphic, and hormonal factors on bone density in a cross-sectional sample of 281 pre- and perimenopausal women age 50-60 years living in Massachusetts. The sample included only women who had intact ovaries and were not currently using estrogen. Information on diet was obtained through a semiquantitative food frequency questionnaire. We measured bone density using single-photon absorptiometry in the non-dominant arm in two sites: the midshaft and the ultradistal radius. We observed no important associations between midshaft bone density and dietary variables but found linear relations between ultradistal radius bone density and body mass index [b = 1.10 gm/cm2 per kg/m2, standard error (SE) = 0.56], follicle-stimulating hormone (FSH) (b = -0.36 gm/cm2 per IU/liter, SE = 0.15), and several nutrients: calcium (b = 0.012 gm/cm2 per mg/day, SE = 0.007), retinol (b = 0.002 gm/cm2 per IU/day, SE = 0.0008), vitamin C (b = 0.025 gm/cm2 per mg/day, SE = 0.013), and vitamin D (b = 0.040 gm/cm2 per IU/day, SE = 0.018). We could not clearly distinguish the independent contribution of these micronutrients, however, because many were commonly ingested together in the form of supplements. Caffeine was inversely associated with bone density (b = -0.035, SE = 0.017) independent of dietary, anthropometric, and hormonal factors. Analyses of individual caffeinated beverages revealed consistent inverse associations for coffee (b = -3.42 gm/cm2 per cups/day, SE = 1.49), tea (b = -2.85 gm/cm2 per cups/day, SE = 1.56), and caffeinated cola (b = -14.0 gm/cm2 per cans/day, SE = 5.1), but not for decaffeinated coffee or decaffeinated cola [corrected]. [ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometry↗