Biomedical subjects

Simin Liu

Publications and source records attributed to Simin Liu.

81 records · Page 5Linked to original sources

PubMed2002

Dietary sugar, glycemic load, and pancreatic cancer risk in a prospective study.

BACKGROUND: Evidence from both animal and human studies suggests that abnormal glucose metabolism plays an important role in pancreatic carcinogenesis. We investigated whether diets high in foods that increase postprandial glucose levels are associated with an increased risk of pancreatic cancer. METHODS: In a cohort of U.S. women (n = 88 802) participating in the Nurses' Health Study, 180 case subjects with pancreatic cancer were diagnosed during 18 years of follow-up. We used frequency of intake of individual foods as reported on a food-frequency questionnaire in 1980 to calculate sucrose, fructose, and carbohydrate intakes; glycemic index (postprandial blood glucose response as compared with a reference food); and glycemic load (glycemic index multiplied by carbohydrate content). Analyses of relative risk (RR) were performed by using multivariable Cox proportional hazards models to adjust for potential confounders. All statistical tests were two-sided. RESULTS: Carbohydrate and sucrose intake were not associated with overall pancreatic cancer risk in this cohort. A statistically nonsignificant 53% increase in risk of pancreatic cancer (RR = 1.53, 95% confidence interval [CI] = 0.96 to 2.45) was observed among women with a high glycemic load intake, and a similar association was observed for fructose intake (RR = 1.57, 95% CI = 0.95 to 2.57). The associations of glycemic load and fructose intakes with pancreatic cancer risk were most apparent among women with elevated body mass index (>or=25 kg/m(2)) or with low physical activity. Among women who were both overweight and sedentary, a high glycemic load was associated with an RR of 2.67 (95% CI = 1.02 to 6.99; highest versus lowest quartile of intake; P for trend =.03), and high fructose was associated with an RR of 3.17 (95% CI = 1.13 to 8.91; P for trend =.04). CONCLUSION: Our data support other findings that impaired glucose metabolism may play a role in pancreatic cancer etiology. A diet high in glycemic load may increase the risk of pancreatic cancer in women who already have an underlying degree of insulin resistance.

Adult↗

PubMed2002

A prospective study of dietary fiber intake and risk of cardiovascular disease among women.

OBJECTIVES: This study was designed to examine the hypothesis that higher intake of dietary fiber is inversely related to the risk of cardiovascular disease (CVD) and myocardial infarction (MI) in a large prospective cohort of women. BACKGROUND: Although dietary fiber has been suggested to reduce the risk of coronary disease, few prospective studies have examined the association between the types and amounts of dietary fiber and CVD risk, particularly among women. METHODS: In 1993, we used a semi-quantitative food frequency questionnaire to assess dietary fiber intake among 39,876 female health professionals with no previous history of CVD or cancer. Women were subsequently followed for an average of six years for incidence of nonfatal MI, stroke, percutaneous transluminal coronary angioplasty, coronary artery bypass graft or death due to CVD confirmed by medical records or death certificates. RESULTS: During 230,006 person-years of follow-up, 570 incident cases of CVD were documented, including 177 MIs. After adjustment for age and randomized treatment status, a significant inverse association was observed between dietary fiber intake and CVD risk. Comparing the highest quintile of fiber intake (median: 26.3 g/day) with the lowest quintile (median: 12.5 g/day), the relative risks (RR) were 0.65 (95% confidence interval [CI]: 0.51, 0.84) for total CVD and 0.46 (95% CI: 0.30, 0.72) for MI. Additional adjustment for CVD risk factors reduced the RRs to 0.79 (95% CI: 0.58, 1.09) for total CVD and 0.68 (95% CI: 0.36, 1.22) for MI. The inverse trends across categories generally remained, although they were no longer statistically significant. Inverse relations were observed between both soluble and insoluble fiber and risk of CVD and MI, and among those who had never smoked and those with body mass index <25. CONCLUSIONS: A higher intake of dietary fiber was associated with a lower risk of CVD and MI, although the association was not statistically significant after further adjusting for multiple confounding factors. Nevertheless, these prospective data generally support current dietary recommendations to increase the consumption of fiber-rich whole grains and fruits and vegetables as a primary preventive measure against CVD.

Aged↗

PubMed2002

Dietary glycemic load and atherothrombotic risk.

Hyperglycemia and hyperinsulinemia are central features of the metabolic syndrome and type 2 diabetes mellitus, which contribute to the pathogenesis of coronary heart disease (CHD). Recent data indicate that increased dietary glycemic load (GL) due to replacing fats with carbohydrates or increasing intake of rapidly absorbed carbohydrates (ie, high glycemic index) can create a self-perpetuating insulin resistance state and predicts greater CHD risk. In this paper, we discuss the historic development of the GI and GL concepts and summarize metabolic experiments and epidemiologic observations relating to clinical utilities of these measures. On balance, increased consumption of low-GI foods leads to improvements in glycemia and dyslipidemia in metabolic studies, and a low-GL diet has been associated with lower risk of type 2 diabetes and CHD in prospective cohort studies. We conclude that decreasing dietary GL by reducing the intake of high-glycemic beverages and replacing refined grain products and potatoes with minimally processed plant-based foods such as whole grains, fruits, and vegetables may reduce CHD incidence in sedentary individuals and populations with a high prevalence of overweight. Because of advances in food-processing technologies and changes in ingredients in our food supply, the composition and physiologic effects of foods are likely to change over time. Future efforts should continue to quantify and monitor the metabolic impacts of different foods, and such information should be routinely incorporated into long-term prospective studies to allow for the assessment of the interactive effects of diets and other metabolic determinants on chronic disease risk.

Coronary Artery Disease↗

PubMed2002

A prospective study of TaqIB polymorphism in the gene coding for cholesteryl ester transfer protein and risk of myocardial infarction in middle-aged men.

BACKGROUND: Molecular variations in the gene coding for the cholesteryl ester transfer protein (CETP) such as the TaqIB polymorphism are associated with higher plasma high-density lipoprotein (HDL) concentration. However, whether this polymorphism is associated with risk of myocardial infarction (MI) is uncertain. METHODS AND RESULTS: In a prospective cohort of 14916 apparently healthy men enrolled in the Physicians' Health Study, allelic status for the TaqIB polymorphism in the CETP gene was determined among 384 participants who subsequently developed a first MI (cases) and among an equal number of age and smoking-matched participants who remained free of cardiovascular disease during follow-up (controls). Overall, the B2B2 genotype was present in 17% of the study participants and was associated with higher HDL cholesterol levels (mean mg/dl [+/- S.D.], 45 +/- 11 for the B1B1 genotype, 48 +/- 13 for the B1B2 genotype and 50 +/- 12 for the B2B2 genotype; P=0.01). However, the risk of developing MI did not differ significantly across these three genotypes. After adjustment for coronary risk factors (but not HDL), the relative risks for future MI were 1.12(95% CI 0.74-1.70) for the B1B2 genotype and 0.95(95% CI 0.54-1.66) for the B2B2 genotype, compared with the B1B1 genotype. In subgroup analysis of individuals with low HDL levels, B2B2 genotype appeared to have a lower risk of MI compared with the B1B1 genotype. However, participants with high HDL were at lower risk of developing MI regardless of their CETP genotype. CONCLUSIONS: In this prospective study of apparently healthy middle-aged US men, carriers of the B2 allele of the TaqIB in the CETP gene had higher HDL concentrations, but did not have lower risk of MI. CONDENSED ABSTRACT: In a cohort of apparently healthy middle-aged US men, the relation between CETP genotype and MI risk was prospectively examined in a nested case-control study. After adjusting for coronary risk factors (but not HDL), the 9-year risk of developing MI did not differ significantly by genotype. Comparing to the B1B1 genotype, the relative risks for future MI were 1.12 (95% CI 0.74-1.70) for the B1B2 genotype and 0.95 (95% CI 0.54-1.66) for the B2B2 genotype.

Carrier Proteins↗

PubMed2002

Intake of refined carbohydrates and whole grain foods in relation to risk of type 2 diabetes mellitus and coronary heart disease.

Recent survey data indicate that more than 50% of all adult Americans are overweight or obese. In parallel with this epidemic of weight gain in the general population, the incidence rate of type 2 diabetes mellitus (DM) is rapidly rising. Although their precise contributions are unclear, dietary factors are thought to affect body weight and the development of insulin resistance. Recent epidemiological data indicate that diets rich in high-fiber whole grains are associated with lower risk of coronary heart disease (CHD) and type 2 DM. These data are consistent with results from recent metabolic experiments, suggesting favorable lipid profiles and glycemic control associated with higher intake of whole grains, but not with refined grains. It seems prudent, therefore, to distinguish whole-grain rather than refined-grain cereal products for the prevention of chronic diseases.

Blood Glucose↗

PubMed2002

Relation between a diet with a high glycemic load and plasma concentrations of high-sensitivity C-reactive protein in middle-aged women.

BACKGROUND: Recent prospective data suggest that intake of rapidly digested and absorbed carbohydrates with a high dietary glycemic load is associated with an increased risk of ischemic heart disease. OBJECTIVE: We examined whether a high dietary glycemic load was associated with elevated hs-CRP concentrations and whether this association was modified by body mass index (BMI; in kg/m(2)). DESIGN: In 244 apparently healthy women, we measured plasma hs-CRP concentrations and determined average dietary glycemic loads with a validated semiquantitative food-frequency questionnaire. Using multiple regression models, we evaluated the association between dietary glycemic load and plasma hs-CRP after adjusting for age; treatment status; smoking status; BMI; physical activity level; parental history of myocardial infarction; history of hypertension, diabetes, and high cholesterol; postmenopausal hormone use; alcohol intake; and other dietary variables. RESULTS: We found a strong and statistically significant positive association between dietary glycemic load and plasma hs-CRP. The median hs-CRP concentration for the lowest quintile of dietary glycemic load was 1.9 mg/L and for the highest quintile was 3.7 mg/L; corresponding multivariate-adjusted geometric means were 1.4 and 3.8 mg/L, respectively (P for trend < 0.01). This association was significantly modified by BMI. Among women with a BMI greater-than-or-equal 25, the multivariate-adjusted geometric mean hs-CRP concentration in the lowest quintile was 1.6 mg/L and in the highest quintile was 5.0 mg/L; however, among women with a BMI < 25, the corresponding means were 1.1 and 3.1 mg/L, respectively (P = 0.01 for interaction). CONCLUSIONS: Dietary glycemic load is significantly and positively associated with plasma hs-CRP in healthy middle-aged women, independent of conventional risk factors for ischemic heart disease. Exacerbation of the proinflammatory process may be a mechanism whereby a high intake of rapidly digested and absorbed carbohydrates increases the risk of ischemic heart disease, especially in overweight women prone to insulin resistance.

Aged↗

PubMed2002

Whole-grain intake is favorably associated with metabolic risk factors for type 2 diabetes and cardiovascular disease in the Framingham Offspring Study.

BACKGROUND: The influence of whole grains on cardiovascular disease risk may be mediated through multiple pathways, eg, a reduction in blood lipids and blood pressure, an enhancement of insulin sensitivity, and an improvement in blood glucose control. OBJECTIVE: The objective was to examine the association between diets rich in whole- or refined-grain foods and several metabolic markers of disease risk in the Framingham Offspring Study cohort. DESIGN: Whole-grain intake and metabolic risk markers were assessed in a cross-sectional study of 2941 subjects. RESULTS: After adjustment for potential confounding factors, whole-grain intake was inversely associated with body mass index (: 26.9 in the lowest and 26.4 in the highest quintile of intake; P for trend = 0.06), waist-to-hip ratio (0.92 and 0.91, respectively; P for trend = 0.005), total cholesterol (5.20 and 5.09 mmol/L, respectively; P for trend = 0.06), LDL cholesterol (3.16 and 3.04 mmol/L, respectively; P for trend = 0.02), and fasting insulin (205 and 199 pmol/L, respectively; P for trend = 0.03). There were no significant trends in metabolic risk factor concentrations across quintile categories of refined-grain intake. The inverse association between whole-grain intake and fasting insulin was most striking among overweight participants. The association between whole-grain intake and fasting insulin was attenuated after adjustment for dietary fiber and magnesium. CONCLUSION: Increased intakes of whole grains may reduce disease risk by means of favorable effects on metabolic risk factors.

Blood Glucose↗

PubMed2002

Whole-grain intake and the risk of type 2 diabetes: a prospective study in men.

BACKGROUND: Certain dietary components may play a role in the prevention of type 2 diabetes. OBJECTIVE: We examined prospectively the associations between whole- and refined-grain intake and the risk of type 2 diabetes in a large cohort of men. DESIGN: Men from the Health Professionals Follow-up Study without a history of diabetes or cardiovascular disease in 1986 (n = 42898) were followed for </=12 y. Intakes of whole and refined grains, measured every 4 y by use of food-frequency questionnaires, were used to predict subsequent type 2 diabetes risk through multivariate analysis. RESULTS: We ascertained 1197 cases of incident type 2 diabetes. After adjustment for age; physical activity; cigarette smoking; alcohol consumption; family history of diabetes; and fruit, vegetable, and energy intakes, the relative risk of type 2 diabetes was 0.58 (95% CI: 0.47, 0.70; P for trend < 0.0001) comparing the highest with the lowest quintile of whole-grain intake. The association was moderately attenuated when additionally adjusted for body mass index (relative risk: 0.70; 95% CI: 0.57, 0.85; P for trend = 0.0006). Intake of refined grains was not significantly associated with risk of type 2 diabetes. After further adjustment for magnesium intake, cereal fiber intake, and glycemic load, the association between whole grains and type 2 diabetes was attenuated and the trend no longer significant. CONCLUSIONS: In men, a diet high in whole grains is associated with a reduced risk of type 2 diabetes in men that may be mediated by cereal fiber. Efforts should be made to replace refined-grain with whole-grain foods.

Adult↗

PubMed2002

Glycemic index, glycemic load, and risk of type 2 diabetes.

The possibility that high, long-term intake of carbohydrates that are rapidly absorbed as glucose may increase the risk of type 2 diabetes has been a long-standing controversy. Two main mechanisms have been hypothesized, one mediated by increases in insulin resistance and the other by pancreatic exhaustion as a result of the increased demand for insulin. During the past decade, several lines of evidence have collectively provided strong support for a relation between such diets and diabetes incidence. In animals and in short-term human studies, a high intake of carbohydrates with a high glycemic index (a relative measure of the incremental glucose response per gram of carbohydrate) produced greater insulin resistance than did the intake of low-glycemic-index carbohydrates. In large prospective epidemiologic studies, both the glycemic index and the glycemic load (the glycemic index multiplied by the amount of carbohydrate) of the overall diet have been associated with a greater risk of type 2 diabetes in both men and women. Conversely, a higher intake of cereal fiber has been consistently associated with lower diabetes risk. In diabetic patients, evidence from medium-term studies suggests that replacing high-glycemic-index carbohydrates with a low-glycemic-index forms will improve glycemic control and, among persons treated with insulin, will reduce hypoglycemic episodes. These dietary changes, which can be made by replacing products made with white flour and potatoes with whole-grain, minimally refined cereal products, have also been associated with a lower risk of cardiovascular disease and can be an appropriate component of recommendations for an overall healthy diet.

Blood Glucose↗