Biomedical subjects

D Spiegelman

Publications and source records attributed to D Spiegelman.

At least 163 records · Page 9Linked to original sources

PubMed1996

Dietary fat and risk of coronary heart disease in men: cohort follow up study in the United States.

OBJECTIVE: To examine the association between fat intake and the incidence of coronary heart disease in men of middle age and older. DESIGN: Cohort questionnaire study of men followed up for six years from 1986. SETTING: The health professionals follow up study in the United States. SUBJECTS: 43 757 health professionals aged 40 to 75 years free of diagnosed cardiovascular disease or diabetes in 1986. MAIN OUTCOME MEASURE: Incidence of acute myocardial infarction or coronary death. RESULTS: During follow up 734 coronary events were documented, including 505 non-fatal myocardial infarctions and 229 deaths. After age and several coronary risk factors were controlled for significant positive associations were observed between intake of saturated fat and risk of coronary disease. For men in the top versus the lowest fifth of saturated fat intake (median = 14.8% v 5.7% of energy) the multivariate relative risk for myocardial infarction was 1.22 (95% confidence interval 0.96 to 1.56) and for fatal coronary heart disease was 2.21 (1.38 to 3.54). After adjustment for intake of fibre the risks were 0.96 (0.73 to 1.27) and 1.72 (1.01 to 2.90), respectively. Positive associations between intake of cholesterol and risk of coronary heart disease were similarly attenuated after adjustment for fibre intake. Intake of linolenic acid was inversely associated with risk of myocardial infarction; this association became significant only after adjustment for non-dietary risk factors and was strengthened after adjustment for total fat intake (relative risk 0.41 for a 1% increase in energy, P for trend < 0.01). CONCLUSIONS: These data do not support the strong association between intake of saturated fat and risk of coronary heart disease suggested by international comparisons. They are compatible, however, with the hypotheses that saturated fat and cholesterol intakes affect the risk of coronary heart disease as predicted by their effects on blood cholesterol concentration. They also support a specific preventive effect of linolenic acid intake.

Adult↗

PubMed1996

Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men.

OBJECTIVE: To examine prospectively the relationship between dietary fiber and risk of coronary heart disease. DESIGN: Cohort study. SETTING: In 1986, a total of 43,757 US male health professionals 40 to 75 years of age and free from diagnosed cardiovascular disease and diabetes completed a detailed 131-item dietary questionnaire used to measure usual intake of total dietary fiber and specific food sources of fiber. MAIN OUTCOME MEASURE: Fatal and nonfatal myocardial infarction (MI). RESULTS: During 6 years of follow-up, we documented 734 cases of MI (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total MI was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal coronary disease (RR, 0.45; 95% CI, 0.28 to 0.72). After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, the RRs were only modestly attenuated. A 10-g increase in total dietary fiber corresponded to an RR for total MI of 0.81 (95% CI, 0.70 to 0.93). Within the three main food contributors to total fiber intake (vegetable, fruit, and cereal), cereal fiber was most strongly associated with a reduced risk of total MI (RR, 0.71; 95% CI, 0.55 to 0.91 for each 10-g increase in cereal fiber per day). CONCLUSIONS: Our results suggest an inverse association between fiber intake and MI. These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease.

Adult↗

PubMed1996

Cohort studies of fat intake and the risk of breast cancer--a pooled analysis.

BACKGROUND: Experiments in animals, international correlation comparisons, and case-control studies support an association between dietary fat intake and the incidence of breast cancer. Most cohort studies do not corroborate the association, but they have been criticized for involving small numbers of cases, homogeneous fat intake, and measurement errors in estimates of fat intake. METHODS: We identified seven prospective studies in four countries that met specific criteria and analyzed the primary data in a standardized manner. Pooled estimates of the relation of fat intake to the risk of breast cancer were calculated, and data from study-specific validation studies were used to adjust the results for measurement error. RESULTS: Information about 4980 cases from studies including 337,819 women was available. When women in the highest quintile of energy-adjusted total fat intake were compared with women in the lowest quintile, the multivariate pooled relative risk of breast cancer was 1.05 (95 percent confidence interval, 0.94 to 1.16). Relative risks for saturated, monounsaturated, and polyunsaturated fat and for cholesterol, considered individually, were also close to unity. There was little overall association between the percentage of energy intake from fat and the risk of breast cancer, even among women whose energy intake from fat was less than 20 percent. Correcting for error in the measurement of nutrient intake did not materially alter these findings. CONCLUSIONS: We found no evidence of a positive association between total dietary fat intake and the risk of breast cancer. There was no reduction in risk even among women whose energy intake from fat was less than 20 percent of total energy intake. In the context of the Western lifestyle, lowering the total intake of fat in midlife is unlikely to reduce the risk of breast cancer substantially.

Adult↗

PubMed1996

Prospective study of beverage use and the risk of kidney stones.

Patients with kidney stones are routinely advised to increase their fluid intake to decrease the risk of stone recurrence. However, there has been no detailed examination to determine whether the effect on recurrence varies by the type of beverage consumed. The authors conducted a prospective study of the relation between the intake of 21 different beverages and the risk of symptomatic kidney stones in a cohort of 45,289 men, 40-75 years of age, who had no history of kidney stones. Beverage use and other dietary information was measured by means of a semiquantitative food frequency questionnaire in 1986. During 6 years of follow-up (242,100 person-years), 753 incident cases of kidney stones were documented. After adjusting simultaneously for age, dietary intake of calcium, animal protein and potassium, thiazide use, geographic region, profession, and total fluid intake, consumption of specific beverages significantly added to the prediction of kidney stone risk (p < 0.001). After mutually adjusting for the intake of other beverages, the risk of stone formation decreased by the following amount for each 240-ml (8-oz) serving consumed daily: caffeinated coffee, 10% (95% confidence interval 4-15%); decaffeinated coffee, 10% (3-16%); tea, 14% (5-22%); beer, 21% (12-30%); and wine, 39% (10-58%). For each 240-ml serving consumed daily, the risk of stone formation increased by 35% (4-75%) for apple juice and 37% (1-85%) for grapefruit juice. The authors conclude that beverage type may have an effect on stone formation that involves more than additional fluid intake alone.

Adult↗

PubMed1996

Self-reported birthweight and history of having been breastfed among younger women: an assessment of validity.

BACKGROUND: Recent evidence suggests potential associations between birthweight and infant feeding history and risk of a variety of health outcomes during adulthood. Because studies may rely on self-reported birthweight and infant feeding history, it is important to assess the validity of this information. METHODS: The authors compared birthweights reported by a sample of 538 women, 27-44 years of age, participating in the Nurses' Healthy Study II (NHSII) cohort, with birthweights recalled by their mothers and with those from state birth records. In addition, we compared participants' self-reported history of having breastfed with their breastfeeding history reported by their mothers. RESULTS: For birthweight, the correlation between reports by the cohort participants and by their mothers was high (Spearman r = 0.75). Compared with weights recorded on state birth records, correlations were 0.74 for reports by cohort participants and 0.85 for reports by their mothers. When comparing NHSII participants' self-report of ever having been breastfed with their mothers' report, sensitivity was 82% and specificity was 86%. For duration of breastfeeding, the Spearman correlation between mother and daughter reports was 0.74. In analyses stratified by four ethnic groups (African-American, Asian, Caucasian, and Hispanic) we observed substantial differences in distribution of birthweight and breastfeeding patterns; however, the degree of validity in reporting them was similar. CONCLUSION: The validity of self-reported birthweight and breastfeeding history by these middle-aged women appears to be high.

Adult↗

PubMed1996

Reproducibility and validity of a self-administered physical activity questionnaire for male health professionals.

We assessed the reproducibility and validity of a self-administered physical activity questionnaire used in a prospective study of 51,529 men. The questionnaire was administered by mail twice to 238 participants 2 years apart. During this interval, the participants completed a past-week recall and a 1-week activity diary at four times corresponding to different seasons throughout a year. Also, a step test was taken by a subset of the study participants. The intraclass correlation coefficients used to measure reproducibility were 0.39 for inactivity, 0.42 for nonvigorous activity, and 0.52 for vigorous activity. The correlations between diary-based and questionnaire-based activity scores, adjusted for variation in the diary measurements, were 0.41 for inactivity, 0.28 for nonvigorous activity, and 0.58 for vigorous activity. The distribution of activity scores was similar between the questionnaires and the average of past-week recalls, indicating the participants' ability to incorporate seasonal variation into their recall on a questionnaire. The correlation between vigorous activity and resting pulse was -0.45, whereas, for the pulse rate after stepping, the correlation was -0.41. These data indicate that this physical activity questionnaire is reproducible and provides a useful measure of average weekly activity, particularly vigorous activity, over a 1-year period.

Adult↗

PubMed1995

Body size and fat distribution as predictors of coronary heart disease among middle-aged and older US men.

Obesity, android fat distribution, and other anthropometric measures have been associated with coronary heart disease in long-term prospective studies. However, fluctuations in weight due to age-related hormonal changes and changes in lifestyle practices may bias relative risk estimates over a long follow-up period. The authors prospectively studied the association between body mass index (BMI) (kg/m2), waist-to-hip ratio, and height as independent predictors of incident coronary heart disease in a 3-year prospective study among 29,122 US men aged 40-75 years in 1986. The authors documented 420 incident coronary events during the follow-up period. Body mass index, waist-to-hip ratio, short stature, and weight gain since age 21 were associated with an increased risk of coronary heart disease. Among men younger than 65, after adjusting for other coronary risk factors, the relative risk was 1.72 (95% confidence interval (CI) 1.10-2.69) for men with BMI of 25-28.9, 2.61 (95% CI 1.54-4.42) for BMI of 29.0-32.9, and 3.44 (95% CI 1.67-7.09) for obese men with BMI > or = 33 compared with lean men with BMI < 23.0. Among men > or = 65 years of age, the association between BMI and risk of coronary heart disease was much weaker. However, in this age group, the waist-to-hip ratio was a much stronger predictor of risk (relative risk = 2.76, 95% CI 1.22-6.23 between extreme quintiles). These results suggest that for younger men, obesity, independent of fat distribution, is a strong risk factor for coronary heart disease. For older men, measures of fat distribution may be better than body mass index at predicting risk of coronary disease.

Adipose Tissue↗

PubMed1995

Changes in plasma lipoprotein concentrations and composition in response to a low-fat, high-fiber diet are associated with changes in serum estrogen concentrations in premenopausal women.

We have investigated the effects of a low-fat, high-fiber diet on plasma lipid and lipoprotein levels and serum sex hormone concentrations in 22 normal premenopausal women (mean age, 25.8 +/- 3.8 years). Participants consumed a baseline diet for 4 weeks (40% of calories as fat, 16% as saturated fatty acids, 8% as polyunsaturated fatty acids, 400 mg/d cholesterol, and 12 g/d dietary fiber) and then a low-fat, high-fiber diet for 8 to 10 weeks (16% to 18% of calories as fat, 4% as saturated fatty acids, 4% as polyunsaturated fatty acids, 150 mg/d cholesterol, and 40 g/d fiber). Blood samples for determination of plasma lipids and serum hormones were obtained during the follicular and luteal phases of the menstrual cycle during both diets. Compared with the baseline diet, the low-fat, high-fiber diet resulted in significant decreases in total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol concentrations during both the follicular and luteal phases (TC, -14% and -16%; LDL cholesterol, -14% and -17%; and HDL cholesterol, -15% and -18%, respectively). During the follicular phase but not the luteal phase on the low-fat, high-fiber diet, women exhibited significant increases in plasma triglyceride ([TG] 22%) and very-low-density lipoprotein (VLDL)-TG (36%) concentrations. During the follicular phase, serum estrone sulfate concentrations decreased by 25% (P < .0001) when subjects were fed the low-fat, high-fiber diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Reproducibility of plasma hormone levels in postmenopausal women over a 2-3-year period.

We evaluated the reproducibility of plasma hormone levels over time in 79 healthy postmenopausal women, ages 51-69 years at baseline, who were not using postmenopausal hormones. Three blood samples were collected between 1989 and 1992 from each of these women. We assessed plasma levels of estradiol, free estradiol, percentage of free estradiol, bioavailable estradiol, percentage of bioavailable estradiol, estrone, estrone sulfate, sex hormone-binding globulin (SHBG), androstenedione, testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and prolactin at each of three sample collections. The means and SD for each of the plasma estrogens, SHBG, and prolactin were similar at each collection. For the androgens, plasma levels tended to decrease over time consistent with an aging effect; decreases with increasing age were statistically significant for androstenedione, dehydroepiandrosterone, and dehydroepiandrosterone sulfate. Intraclass correlation coefficients (ICCs) ranged from 0.92 (95% confidence interval = 0.89-0.95) for SHBG to 0.53 (95% confidence interval = 0.43-0.69) for prolactin. Most correlations were at least 0.70. The ICCs did not vary by age or time since menopause. Women who changed weight over the course of the study tended to have lower ICCs for a number of the hormones, although these differences were not statistically significant. These data indicate that, for most of these plasma hormones, a single measurement can reliably categorize average levels over at least a 3-year period in postmenopausal women.

Age Distribution↗

PubMed1994

Validation of the Gail et al. model for predicting individual breast cancer risk.

BACKGROUND: The Gail et al. model is considered the best available means for estimating an individual woman's risk of developing breast cancer. Such estimates are useful in decision making on the part of women, in designing prevention trials, and in targeting screening and prevention efforts. PURPOSE: Our purpose was to evaluate the ability of the model to accurately predict individual breast cancer risk, using a large population independent of the one from which the model was derived. METHODS: We compared the number of cancer cases predicted by the model to the actual number of cases observed in the Nurses' Health Study. The study population was 115,172 women who did not have breast cancer at the beginning of the study. Questionnaires were sent to participants every 2 years, seeking data on risk factors and diagnoses of breast cancer. Follow-up compliance was 95% over the 12-year study period. RESULTS: The model over-predicted absolute breast cancer risk by 33% (95% confidence interval [CI] = 28%-39%), with the overprediction more than twofold among premenopausal women (95% CI = 1.9-2.2), among women with extensive family history of breast cancer (95% CI = 1.1-3.9), and among women with age at first birth younger than 20 years (95% CI = 1.3-4.7). The correlation coefficient between observed and predicted risk was 0.67, indicating that the model is less than satisfactory for ranking individual levels of breast cancer risk. Overprediction occurred at all deciles of predicted risk. CONCLUSIONS: The model's performance is unsatisfactory for estimating breast cancer risk for individual women aged 25-61 years who do not participate in annual screening. Lower mammography screening rates in the Nurses' Health Study may account for some, but not all, of the discrepancy between observed and predicted cases. IMPLICATIONS: A recent modification of the model by the tamoxifen trial investigators is likely to have provided accurate power calculations. This modified form of the model should be useful for planning other large, population-based studies.

Adult↗

PubMed1994

Human adipose alpha-tocopherol and gamma-tocopherol kinetics during and after 1 y of alpha-tocopherol supplementation.

Alpha-tocopherol and gamma-tocopherol were monitored in human adipose by using needle biopsies in four subjects during a 1-y supplementation trial with 800 mg all-rac-alpha-tocopherol/d, and for 1 additional year after cessation of supplement. Some increase in adipose alpha-tocopherol (per milligram adipose cholesterol) and a more consistent decrease in gamma-tocopherol were observed during the supplementation period. The alpha-tocopherol/gamma-tocopherol ratio rose consistently during supplementation and fell only gradually after the supplement was stopped. We estimate that > or = 2 y are required for the alpha-tocopherol/gamma-tocopherol ratio to reach a new steady state after a change in alpha-tocopherol intake. In a cross-sectional measurement in five subjects who reported long-term use of alpha-tocopherol supplements (> or = 250 mg/d), and in five other subjects who reported no supplement use, the adipose alpha-tocopherol/gamma-tocopherol ratio clearly discriminated between the two groups (P < 0.002). This ratio may be of value in ranking individuals according to long-term alpha-tocopherol intake.

Adipose Tissue↗

PubMed1994

Clinical utility of chest auscultation in common pulmonary diseases.

In this investigation we applied the techniques of lung sound mapping and time-expanded wave-form analysis to four common diseases that involve the lung: interstitial pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), and pneumonia (Pn). Twenty subjects were studied in each group. We also studied 15 subjects without evidence of lung disease. Differences in timing, character, and location were observed, which allowed separation among these groups. Multiple logistic regression models were created and tested by the bootstrap method. Regression models correctly classified 68 and 79% of subjects. Area under the receiver operating curve ranged from 0.96 for IPF and CHF to 0.80 for COPD. We conclude that auscultatory differences exist among common pulmonary conditions and that statistical models based on auscultatory data perform well in predicting diagnostic categories.

Aged↗

PubMed1993

Vitamin A supplementation and dietary vitamin A in relation to the risk of xerophthalmia.

We examined the effect of 60-mg (200,000-IU) supplements of vitamin A administered every 6 mo on the incidence of xerophthalmia among preschool children who were free of eye symptoms and signs of vitamin A deficiency. We also prospectively studied the relationship of dietary vitamin A intake with the same endpoint. After 18 mo of follow-up, 400 children developed xerophthalmia during 80,104 child-periods of follow-up. Vitamin A supplementation only modestly reduced the risk of xerophthalmia (relative risk 0.88, 95% confidence interval 0.72-1.07, P = 0.19). On the other hand, total dietary vitamin A intake was strongly associated with reduced risk of xerophthalmia; the multivariate relative risk when children in extreme quintiles were compared was 0.38 (95% confidence interval 0.19-0.74; P for trend over quintiles = 0.002). These results emphasize the need for further data on factors that modify the bioavailability of large-dose vitamin A supplements. Increased consumption of inexpensive vegetables and fruits is highly likely to reduce significantly the risks of vitamin A deficiency, including nutritional blindness in developing countries.

Child↗

PubMed1992

Correction of logistic regression relative risk estimates and confidence intervals for random within-person measurement error.

Frequently, covariates used in a logistic regression are measured with error. The authors previously described the correction of logistic regression relative risk estimates for measurement error in one or more covariates when a "gold standard" is available for exposure assessment. For some exposures (e.g., serum cholesterol), no gold standard exists, and one must assess measurement error via a reproducibility substudy. In this paper, the authors present measurement error methods for logistic regression when there is error (possibly correlated) in one or more covariates and one has data from both a main study and a reproducibility substudy. Confidence intervals from this procedure reflect error in parameter estimates from both studies. These methods are applied to the Framingham Heart Study, where the 10-year incidence of coronary heart disease is related to several coronary risk factors among 1,731 men disease-free at examination 4. Reproducibility data are obtained from the subgroup of 1,346 men seen at examinations 2 and 3. Estimated odds ratios comparing extreme quintiles for risk factors with substantial error were increased after correction for measurement error (serum cholesterol, 2.2 vs. 2.9; serum glucose, 1.3 vs. 1.5; systolic blood pressure, 2.8 vs. 3.8), but were generally decreased or unchanged for risk factors with little or no error (body mass index, 1.6 vs. 1.6; age 65-69 years vs. 35-44 years, 4.3 vs. 3.8; smoking, 1.7 vs. 1.7).

Adult↗

PubMed1992

Dietary fat and fiber in relation to risk of breast cancer. An 8-year follow-up.

OBJECTIVE: To address the hypotheses that dietary fat increases and fiber decreases the risk of breast cancer. DESIGN: Prospective cohort study with dietary assessment at baseline, using a validated, self-administered food frequency questionnaire. SETTING/PARTICIPANTS: 89,494 women in the Nurses' Health Study who were 34 through 59 years of age in 1980 and who were followed up for 8 years (> 95% complete). RESULTS: 1439 incident cases of breast cancer were diagnosed, including 774 among postmenopausal women. After adjustment for age, established risk factors, and total energy intake, we observed no evidence of any positive association between total fat intake and breast cancer incidence (relative risks [RRs] for increasing quintiles of fat intake were 1.0, 0.85, 0.96, 0.91, and 0.90; 95% confidence interval for highest vs lowest quintile, 0.77 to 1.07). Among postmenopausal women alone, corresponding RRs were 1.0, 0.89, 1.00, 0.95, and 0.91. Comparing extreme deciles of total fat intake (> or = 49% vs < 29% of total energy intake), the RR was 0.86 (95% confidence interval, 0.67 to 1.08). A similar absence of any positive association was observed without adjustment for energy intake; for tumors less than 2 cm as well as 2 cm or greater in diameter; for saturated, monounsaturated, and polyunsaturated fat; and after excluding the first 4 years of follow-up. Also, we found no suggestion of any positive association when using a more detailed and precise dietary questionnaire completed in 1984 (666 subsequent cases), even when women consuming less than 25% of energy from fat were used as the comparison group. No suggestion of a protective effect of dietary fiber was observed (RRs for increasing quintiles were 1.0, 0.95, 0.93, 1.02, and 1.02). CONCLUSIONS: These data provide evidence against both an adverse influence of fat intake and a protective effect of fiber consumption by middle-aged women on breast cancer incidence over 8 years. Nevertheless, the positive association between intake of animal fat and risk of colon cancer observed in many studies provides ample reason to limit this source of energy.

Adult↗

PubMed1992

Absolute fat mass, percent body fat, and body-fat distribution: which is the real determinant of blood pressure and serum glucose?

Associations of body mass index (BMI), absolute fat mass, percent body fat, and regional fat distribution with concentrations of fasting blood glucose and blood pressure were examined cross-sectionally in 1551 men and women aged 15-79 y from two study centers. Measurements included height, weight, multiple skinfold thicknesses, body density by underwater weighing, and waist and hip girths. Three principal findings emerged: 1) Absolute overall body mass and fat mass were stronger predictors of blood pressure and blood glucose than were relative fat mass, after age, height, and current cigarette-smoking status were adjusted for; 2) when diastolic blood pressure and serum glucose were used as the external validity criteria, densitometry was not a "gold standard" for body composition associated with risk for increased blood pressure and serum glucose; and 3) BMI was as good a predictor of blood pressure and glucose as was any other measure of body fat in nearly all analyses.

Adipose Tissue↗

PubMed1991

Cost-efficient study designs for binary response data with Gaussian covariate measurement error.

When mismeasurement of the exposure variable is anticipated, epidemiologic cohort studies may be augmented to include a validation study, where a small sample of data relating the imperfect exposure measurement method to the better method is collected. Optimal study designs (i.e., least expensive subject to specified power constraints) are developed that give the overall sample size and proportion of the overall sample size allocated to the validation study. If better exposure measurements can be collected on a sample of subjects, an optimal design can be suggested that conforms to realistic budgetary constraints. The properties of three designs--those that include an internal validation study, those where the validated subsample is derived from subjects external to the primary investigation, and those that use the better method of exposure assessment on all subjects--are compared. The proportion of overall study resources allocated to the validation substudy increases with increasing sample disease frequency, decreasing unit cost of the superior exposure measurement relative to the imperfect one, increasing unit cost of outcome ascertainment, increasing distance between two alternative values of the relative risk between which the study is designed to discriminate, and increasing magnitude of hypothesized values. This proportion also depends in a nonlinear fashion on the severity of measurement error, and when the validation study is internal, measurement error reaches a point after which the optimal design is the smaller, fully validated one.

Cohort Studies↗

PubMed1990

Correction of logistic regression relative risk estimates and confidence intervals for measurement error: the case of multiple covariates measured with error.

If several risk factors for disease are considered in the same multiple logistic regression model, and some of these risk factors are measured with error, the point and interval estimates of relative risk corresponding to any of these factors may be biased either toward or away from the null value. A method is provided for correcting point and interval estimates of relative risk obtained from logistic regression for measurement error in one or more continuous variables. The method requires a separate validation study to estimate the coefficients from the multivariate linear regression model relating the surrogate variables to the vector of true risk factors. Similar methods have been suggested by other authors, but none provides a means of correcting the confidence intervals which include a component of variability due to estimation of the measurement error parameters from a validation study. An example is provided from a prospective study of dietary fat, calories, and alcohol in relation to breast cancer, and from a validation study of the questionnaire used to assess these nutrients. Before correcting for measurement error, the age-adjusted relative risk for a 25 g increment in alcohol intake was 1.33 (95% confidence interval (CI) 1.14-1.55); after correcting for measurement error, the relative risk increased to 1.62 (95% CI 1.23-2.12). Similarly, for a 10 g increment in saturated fat intake, the age-adjusted relative risk was 0.94 (95% CI 0.83-1.06); after correcting for measurement error, the relative risk was 0.84 (95% CI 0.59-1.20). These results indicate that the failure to find a substantial positive association between breast cancer risk and saturated fat intake cannot be explained by measurement error in fat, calories, or alcohol.

Bias↗