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Biomedical subjects

Ira S Ockene

Publications and source records attributed to Ira S Ockene.

15 recordsLinked to original sources
PubMed2006

Methodology for adding glycemic index and glycemic load values to 24-hour dietary recall database.

OBJECTIVES: We describe a method of adding the glycemic index (GI) and glycemic load (GL) values to the nutrient database of the 24-hour dietary recall interview (24HR), a widely used dietary assessment. We also calculated daily GI and GL values from the 24HR. METHODS: Subjects were 641 healthy adults from central Massachusetts who completed 9067 24HRs. The 24HR-derived food data were matched to the International Table of Glycemic Index and Glycemic Load Values. The GI values for specific foods not in the table were estimated against similar foods according to physical and chemical factors that determine GI. Mixed foods were disaggregated into individual ingredients. RESULTS: Of 1261 carbohydrate-containing foods in the database, GI values of 602 foods were obtained from a direct match (47.7%), accounting for 22.36% of dietary carbohydrate. GI values from 656 foods (52.1%) were estimated, contributing to 77.64% of dietary carbohydrate. The GI values from three unknown foods (0.2%) could not be assigned. The average daily GI was 84 (SD 5.1, white bread as referent) and the average GL was 196 (SD 63). CONCLUSION: Using this methodology for adding GI and GL values to nutrient databases, it is possible to assess associations between GI and/or GL and body weight and chronic disease outcomes (diabetes, cancer, heart disease). This method can be used in clinical and survey research settings where 24HRs are a practical means for assessing diet. The implications for using this methodology compel a broader evaluation of diet with disease outcomes.

Blood Glucose↗
PubMed2006

Association between carbohydrate intake and serum lipids.

BACKGROUND: The effect of dietary carbohydrate on blood lipids has received considerable attention in light of the current trend in lowering carbohydrate intake for weight loss. OBJECTIVES: To evaluate the association between carbohydrate intake and serum lipids. METHODS: Blood samples and 24-hour dietary and physical activity recall interviews were obtained from each subject at quarterly intervals for five consecutive quarters between 1994 and 1998 from 574 healthy adults in Central Massachusetts. Relationships between serum lipids and dietary carbohydrate factors were assessed using linear mixed models and adjusting for other risk factors known to be related to blood lipids. Both cross-sectional and longitudinal results were reported. RESULTS: Cross-sectional analysis results from this study suggest that higher total carbohydrate intake, percentage of calories from carbohydrate, glycemic index (GI) and/or glycemic load (GL) are related to lower high-density lipoprotein cholesterol (HDL-C) and higher serum triacylglycerol levels, while higher total carbohydrate intake and/or GL are related to lower total and low-density lipoprotein cholesterol (LDL-C) levels. In a one-year longitudinal analysis, GL was positively associated with total and LDL-C levels, and there was an inverse association between percentage of calories from carbohydrate and HDL-C levels. CONCLUSIONS: Results suggest that there is a complex and predominantly unfavorable effect of increased intake of highly processed carbohydrate on lipid profile, which may have implications for metabolic syndrome, diabetes, and coronary heart disease. Further studies in the form of randomized controlled trials are required to investigate these associations and determine the implications for lipid management.

Adult↗
PubMed2006

Association between dietary fiber and serum C-reactive protein.

BACKGROUND: High sensitivity C-reactive protein (CRP) is a marker of acute inflammation recently recognized as an independent predictor of future cardiovascular disease and diabetes. The identification of modifiable factors, such as diet, that influence serum CRP concentrations may provide the means for reducing the risk of these diseases. Data on longitudinal associations between dietary fiber intake and CRP are currently lacking. OBJECTIVE: The purpose of this study was to examine longitudinal associations between dietary fiber intake and CRP. DESIGN: Data collection took place at baseline and quarterly (every 13 wk) thereafter for a total of 5 visits, each including measurements of body composition, CRP, diet, and physical activity. Relations between serum CRP and dietary fiber were assessed by using linear mixed models and logistic regression, adjusted for covariates. RESULTS: A total of 524 subjects had multiple measurements of CRP and dietary factors. The average total dietary fiber intake was 16.11 g/d. Average serum CRP was 1.78 mg/L. We observed an inverse association between intake of total dietary fiber (separately for soluble and insoluble fiber) and CRP concentrations in both cross-sectional and longitudinal analyses. The likelihood of elevated CRP concentrations was 63% lower (OR: 0.37; 95% CI: 0.16, 0.87) in participants in the highest quartile of total fiber intake than in participants in the lowest quartile. CONCLUSIONS: Our results suggest that dietary fiber is protective against high CRP, which supports current recommendations for a diet high in fiber.

Adult↗
PubMed2005

Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation.

BACKGROUND: Increased low density lipoprotein cholesterol (LDL-C) is an established risk factor for the development of coronary artery disease (CAD). Recent guidelines detail specific LDL-C cutpoints for therapeutic goals. In practice, LDL-C is usually derived from the Friedewald formula (FF). This calculation is known to be inaccurate with serum triglyceride (TG) concentrations >4.52 mmol/l, however, its accuracy among relatively healthy patient cohorts with TG concentrations < or =4.52 mmol/l is less well studied. METHODS: We studied 661 ambulatory adults with TG concentrations < or =4.52 mmol/l and no overt CAD. Fasting venous lipid panels were obtained. LDL-C was calculated from the FF and also directly measured with the LipiDirect Magnetic LDL assay. Linear regression and paired t-test analyses were performed. RESULTS: Calculated and directly measured LDL-C concentrations were significantly different (4.26+/-0.88 vs. 4.83+/-1.06 mmol/l respectively, p<0.0001). In 93% of measurements directly measured LDL-C exceeded calculated LDL-C. Although calculated and directly measured LDL-C concentrations were related (R=0.90), the discrepancy between them increased linearly with increasing TG concentrations (R=0.67) and clinically important differences existed at normal or slightly increased TG concentrations. Concordant results for NCEP ATP-III risk categories were present for only 48.1% of samples. CONCLUSIONS: Significant differences between calculated and directly measured LDL-C using the LipiDirect Magnetic LDL assay exist in healthy subjects with TG < or =4.52 mmol/l. These differences are linearly related to TG concentrations and occur frequently at relatively low TG concentrations.

Adult↗
PubMed2005

Association between dietary carbohydrates and body weight.

The role of dietary carbohydrates in weight loss has received considerable attention in light of the current obesity epidemic. The authors investigated the association of body mass index (weight (kg)/height (m)(2)) with dietary intake of carbohydrates and with measures of the induced glycemic response, using data from an observational study of 572 healthy adults in central Massachusetts. Anthropometric measurements, 7-day dietary recalls, and physical activity recalls were collected quarterly from each subject throughout a 1-year study period. Data were collected between 1994 and 1998. Longitudinal analyses were conducted, and results were adjusted for other factors related to body habitus. Average body mass index was 27.4 kg/m(2) (standard deviation, 5.5), while the average percentage of calories from carbohydrates was 44.9 (standard deviation, 9.6). Mean daily dietary glycemic index was 81.7 (standard deviation, 5.5), and glycemic load was 197.8 (standard deviation, 105.2). Body mass index was found to be positively associated with glycemic index, a measure of the glycemic response associated with ingesting different types of carbohydrates, but not with daily carbohydrate intake, percentage of calories from carbohydrates, or glycemic load. Results suggest that the type of carbohydrate may be related to body weight. However, further research is required to elucidate this association and its implications for weight management.

Adult↗
PubMed2005

Effect of soy protein containing isoflavones on blood lipids in moderately hypercholesterolemic adults: a randomized controlled trial.

BACKGROUND: Dietary intake of soy protein with isoflavones may be associated with reductions in serum cholesterol. OBJECTIVES: To compare the effects of a water-washed soy protein concentrate with a milk-protein based control on blood lipid levels in hyperlipidemic men and women. METHODS: A randomized, double-blind, controlled clinical trial including 159 subjects. After a 3-week run-in period during which all subjects consumed a milk protein-based supplement, participants were randomized into one of two groups: a control group (continued milk protein) and an intervention group (soy protein) for a five-week period. Fasting venous blood draws for lipid measurement were obtained at baseline, towards the end of the run-in period and at the end of the intervention. Blood isoflavone concentrations were measured at the end of the study. RESULTS: Blood lipid levels were not significantly different between groups at any point in time; and there were no significant associations between blood isoflavones and lipid levels. Significant decreases in total cholesterol (19 mg/dL), and LDL-cholesterol (11 mg/dL), were observed during the run-in period, with no further decreases in lipids during the intervention period in either group. CONCLUSIONS: These results do not support the hypothesis that water-washed soy protein has an effect on blood lipids. Several hypotheses are discussed, highlighting the selective nature of the effect of soy consumption in the population. The cholesterol-lowering effect during the run-in period may be explained by the "regression to the mean effect" and by other factors related to study participation, mainly nutrient displacement induced by the protein supplement.

Adult↗
PubMed2004

Seasonal variation in serum cholesterol levels: treatment implications and possible mechanisms.

BACKGROUND: A variety of studies have noted seasonal variation in blood lipid levels. Although the mechanism for this phenomenon is not clear, such variation could result in larger numbers of people being diagnosed as having hypercholesterolemia during the winter. METHODS: We conducted a longitudinal study of seasonal variation in lipid levels in 517 healthy volunteers from a health maintenance organization serving central Massachusetts. Data collected during a 12-month period for each individual included baseline demographics and quarterly anthropometric, blood lipid, dietary, physical activity, light exposure, and behavioral information. Data were analyzed using sinusoidal regression modeling techniques. RESULTS: The average total cholesterol level was 222 mg/dL (5.75 mmol/L) in men and 213 mg/dL (5.52 mmol/L) in women. Amplitude of seasonal variation was 3.9 mg/dL (0.10 mmol/L) in men, with a peak in December, and 5.4 mg/dL (0.14 mmol/L) in women, with a peak in January. Seasonal amplitude was greater in hypercholesterolemic participants. Seasonal changes in plasma volume explained a substantial proportion of the observed variation. Overall, 22% more participants had total cholesterol levels of 240 mg/dL or greater (> or =6.22 mmol/L) in the winter than in the summer. CONCLUSIONS: This study confirms seasonal variation in blood lipid levels and suggests greater amplitude in seasonal variability in women and hypercholesterolemic individuals, with changes in plasma volume accounting for much of the variation. A relative plasma hypervolemia during the summer seems to be linked to increases in temperature and/or physical activity. These findings have implications for lipid screening guidelines. Further research is needed to better understand the effects of a relative winter hemoconcentration.

Adult↗
PubMed2003

Association between eating patterns and obesity in a free-living US adult population.

Some studies have suggested that eating patterns, which describe eating frequency, the temporal distribution of eating events across the day, breakfast skipping, and the frequency of eating meals away from home, may be related to obesity. Data from the Seasonal Variation of Blood Cholesterol Study (1994-1998) were used to evaluate the relation between eating patterns and obesity. Three 24-hour dietary recalls and a body weight measurement were collected at five equally spaced time points over a 1-year period from 499 participants. Data were averaged for five time periods, and a cross-sectional analysis was conducted. Odds ratios were adjusted for other obesity risk factors including age, sex, physical activity, and total energy intake. Results indicate that a greater number of eating episodes each day was associated with a lower risk of obesity (odds ratio for four or more eating episodes vs. three or fewer = 0.55, 95% confidence interval: 0.33, 0.91). In contrast, skipping breakfast was associated with increased prevalence of obesity (odds ratio = 4.5, 95% confidence interval: 1.57, 12.90), as was greater frequency of eating breakfast or dinner away from home. Further investigation of these associations in prospective studies is warranted.

Adult↗
PubMed2003

Barriers to preventive interventions for coronary heart disease.

Many barriers exist to the delivery of preventive services by cardiologists and other physicians. Appropriate training and the development of supportive infrastructures can effectively overcome these barriers. In addition, institutional priorities must change to encourage such efforts. Cardiologists must continue to recognize the importance of risk-factor modification, and training programs in cardiology should teach appropriate counseling techniques, the use of risk-factor-lowering pharmacologic agents, and the manner in which cardiologists should interface with dietitians and other ancillary personnel [77]. In addition, it is important to recognize and teach, both didactically and by example, that counseling patients and carrying out long-term preventive interventions can be as gratifying and interesting as performing dramatic procedures that, although valuable and rewarding, take place at a very late point in the patient's clinical course, a point that might have been averted by greater attention to risk-factor modification. Increasingly, the public and governmental agencies are becoming involved in encouraging such an approach [66], and health care provider groups [78] and organizations [67] are also facilitating the development of a more comprehensive approach to the delivery of preventive intervention [79].

Coronary Disease↗
PubMed2003

Body mass index, but not physical activity, is associated with C-reactive protein.

UNLABELLED: Elevated high-sensitivity c-reactive protein (hs-CRP) is associated with increased risk of future first and recurrent coronary events and has been associated with both high body mass index (BMI) and low physical activity in cross sectional studies. PURPOSE: To longitudinally examine the effects of BMI and both current and previous-year physical activity on hs-CRP in healthy men and women (N = 109). METHODS: BMI and hs-CRP were measured five times (baseline and quarterly) over 1 yr. Current physical activity was assessed 12-15 times during the study via 24-h recall. Previous-year physical activity was assessed using the Baecke questionnaire at baseline. RESULTS: Mean BMI and hs-CRP were unchanged over the course of the study, but current physical activity increased on visit 3. Average hs-CRP was not related to average current physical activity or to natural changes in current physical activity across the five visits. Additionally, current physical activity on any given visit was not associated with hs-CRP on the following visit. When current physical activity, BMI, age, gender, and smoking were included in the statistical model, only BMI was significantly related to hs-CRP (P < 0.001). Average hs-CRP was significantly correlated with average BMI (r = 0.50; P < 0.001) but was not related to previous-year (Baecke) physical activity levels (r = 0.02; P = 0.89). When subjects were grouped by BMI (<25 kg.m-2, 25-29.9 kg x m-2, >30 kg x m-2) hs-CRP was significantly greater in obese (3.2 +/- 1.9 mg.L-1) and overweight (2.1 +/- 1.7 mg x L-1) than normal weight (1.1 +/- 1.0 mg.L-1) subjects (ANOVA P < 0.05). Current physical activity was similar between the three BMI groups at all times, and was unrelated to hs-CRP in all groups, throughout the study period. CONCLUSION: These data indicate that BMI, but not previous-year or current physical activity, predicts hs-CRP.

Adult↗
PubMed2002

Moderate to vigorous physical activity and risk of upper-respiratory tract infection.

PURPOSE: A "J"-shaped model has been proposed to describe the relationship between physical activity and risk of upper-respiratory tract infection (URTI). However, little epidemiologic evidence is available to support the contention that moderately active individuals are at lowest risk of URTI. This investigation examined differences in URTI risk between physically inactive and moderately active adults. METHODS: Observational study of 547 healthy adults (49% women) aged 20-70 yr reported URTI events at 90-d intervals over 12-month of follow-up (5 evaluations). Three 24-h physical activity recalls per evaluation were obtained and averaged to quantify total moderate-vigorous activity (> or =3.0 metabolic equivalents [MET]). Associations between URTI and physical activity levels were estimated using incidence rate ratios (IRR) derived using Poisson regression while adjusting for a number of potential confounders including age, education, anxiety, cynicism, and selected dietary factors. RESULTS: Men and women reported 1.2 (1.4) and 1.2 (1.2) URTI events per year, respectively (mean [(SD]). Adjusting for gender and potential confounders, the IRR for less than 3.93, 3.94-7.15, 7.16-11.95, and > or = 11.96 MET-h.d(-1) among men, and less than 2.38, 2.39-4.09, 4.10-6.24, and > or = 6.25 MET-h.d(-1) among women, were 1.00 (referent), 0.87 (95% confidence interval [CI], 0.70-1.07), 0.88 (95% CI, 0.71-1.09), and 0.77 (95% CI, 0.62-0.95), respectively (P(trend) = 0.03). This effect was stronger in men (P(trend) = 0.03) than women (P(trend) = 0.17), although at similar expenditure levels (6-7 MET-h.d-1), risk was reduced by about 20% in men and women. Risk reduction was most pronounced in the fall of the year (P(trend) = 0.02). CONCLUSIONS: These data support the hypothesis that moderate levels of physical activity are associated with a reduced risk for URTI.

Adult↗