The internal validity of a dietary pattern analysis. The Framingham Nutrition Studies.

STUDY OBJECTIVES: To examine the internal validity of a dietary pattern analysis and its ability to discriminate clusters of people with similar dietary patterns using independently assessed nutrient intakes and heart disease risk factors. DESIGN AND PARTICIPANTS: Population based study characterising dietary patterns using cluster analysis applied to data from the semiquantitative Framingham food frequency questionnaire collected from 1942 women ages 18-76 years, between 1984-88. SETTING: Framingham, Massachusetts. MAIN RESULTS: Of 1942 women included in the cluster analysis, 1828 (94%) were assigned to one of the five dietary pattern clusters: Heart Healthy, Light Eating, Wine and Moderate Eating, High Fat, and Empty Calorie. Dietary patterns differed substantially in terms of individual nutrient intakes, overall dietary risk, heart disease risk factors, and predicted heart disease risk. Women in the Heart Healthy cluster had the most nutrient dense eating pattern, the lowest level of dietary risk, more favourable risk factor levels, and the lowest probability of developing heart disease. Those in the Empty Calorie cluster had a less nutritious dietary pattern, the greatest level of dietary risk, a heavier burden of heart disease risk factors, and a relatively higher probability of developing heart disease. Cluster reproducibility using discriminant analysis showed that 80% of the sample was correctly classified. The cluster technique was highly sensitive and specific (75% to 100%). CONCLUSIONS: These findings support the internal validity of a dietary pattern analysis for characterising dietary exposures in epidemiological research. The authors encourage other researchers to explore this technique when investigating relations between nutrition, health, and disease.

Nutritional risk in an urban homebound older population. The nutrition and healthy aging project.

PURPOSE: To establish the prevalence of nutritional problems and their related socio-demographic and health-related risk factors in the homebound elderly population. METHODS: Subjects included 239 men and women, ages 65 to 105 years. Trained, two-person field teams conducted comprehensive in-home assessments. Medical record reviews assessed co-morbidity and medication use. RESULTS: The majority of these urban study subjects are of very advanced age (mean age 81 years), female (72%), non-white (73%), living alone (51%), of low income (76%), and somewhat socially isolated (26% had no weekly social contact). More older women than men were widowed (60 vs. 33%, respectively) and poor (80 vs. 67%). The disease burden and functional dependency were both high in men and women; 77% had three or more chronic medical conditions; 76% were functionally dependent in one or more ADL's and 95% in one or more IADL's. Poor dietary quality was universal in these older men and women; half or more consumed diets that deviated from recommended standards for at least 13 of the 24 nutritional guidelines studied. Five percent of subjects were underweight (Body Mass Index (BMI) <18.5); 22% were overweight (BMI 25.0-29.9); and 33% were obese (BMI >30.0). Fasting albumin, hemoglobin, and absolute lymphocyte concentrations were borderline to very low in 18-32%. Dyslipidemia was more common in women; however, men and women had similar Total:HDL cholesterol ratios. CONCLUSIONS: Nutritional status is poor in homebound persons of very advanced age with substantial co-morbidity and functional dependency. The complexities of nutritional risk necessitate multi-disciplinary and individualized nutritional intervention strategies.

Nutritional research within the Framingham Heart Study.

Fifty years of research at the Framingham Heart Study have made important contributions to the diagnosis and treatment of cardiovascular disease (CVD). Within the scope of this prospective population-based cohort study, research investigations from the Framingham Nutrition Studies have developed and advanced nutritional epidemiologic methods, many of which are highlighted here. Ongoing nutrition research explores relationship between diet, nutritional status, and the development of chronic diseases, including CVD. This paper summarizes key findings from decades of nutrition research within the Framingham Heart Study. Cross-sectional and longitudinal investigations are described, including recent research on dietary patterns and coronary heart disease risk among women. Implications for the development of national nutrition policy, population-based dietary guidance for chronic disease prevention, and nutrition-related health promotion campaigns for CVD risk reduction are discussed.

Validation of a dietary pattern approach for evaluating nutritional risk: the Framingham Nutrition Studies.

OBJECTIVE: To validate the use of cluster analysis for characterizing population dietary patterns. DESIGN: Cluster analysis was applied to a food frequency questionnaire to define dietary patterns. Independent estimates of nutrient intake were derived from 3-day food records. Heart disease risk factors were assessed using standardized protocols in a clinic setting. SETTING: Adult women (n = 1,828) participating in the Framingham Offspring-Spouse study. STATISTICAL ANALYSES: Age-adjusted mean nutrient intakes were determined for each cluster. Analysis of covariance was used to evaluate pairwise differences in intake across clusters. Compliance with published recommendations was determined for selected heart disease risk factors. Differences in age-adjusted compliance across clusters were evaluated using logistic regression. RESULTS: Cluster analysis identified 5 distinct dietary patterns characterized by unique food behaviors and significantly different nutrient intake profiles. Patterns rich in fruits, vegetables, grains, low-fat dairy, and lean protein foods resulted in higher nutrient density. Patterns rich in fatty foods, added fats, desserts, and sweets were less nutrient-dense. Women who consumed an Empty Calorie pattern were less likely to achieve compliance with clinical risk factor guidelines in contrast to most other groups of women. CONCLUSIONS: Cluster analysis is a valid tool for evaluating nutrition risk by considering overall patterns and food behaviors. This is important because dietary patterns appear to be linked with other health-related behaviors that confer risk for chronic disease. Therefore, insight into dietary behaviors of distinct clusters within a population can help to design intervention strategies for prevention and management of chronic health conditions including obesity and cardiovascular disease.

Population nutrient intake approaches dietary recommendations: 1991 to 1995 Framingham Nutrition Studies.

OBJECTIVE: To estimate population nutrient intake levels and to assess adherence to current dietary recommendations for health promotion and disease prevention. DESIGN: Cross-sectional analysis of nutrient intake estimated from 3-day food records. Median macronutrient and micronutrient intake levels for men, women, and the total population are reported along with the proportions of men and women who achieved intakes compatible with nutrient goals defined by published guidelines. SETTING: Adult participants (2,520: 1,375 women and 1,145 men) in the Framingham Offspring-Spouse Study surveyed between 1991 and 1995. STATISTICAL ANALYSES: chi 2 Analyses were used to test for gender differences in the proportions of persons who had intakes that met nutrient guidelines. RESULTS: Population intake levels of certain key nutrients, including total and saturated fat, appear to be approaching recommended levels. High proportions of the Framingham population (70% or more) met current recommendations for intakes of protein, polyunsaturated and monounsaturated fat, cholesterol, alcohol, vitamins C and B-12, and folacin. About half or fewer met guidelines for carbohydrate; total and saturated fat; fiber; beta carotene; vitamins A, E, and B-6; calcium; and sodium. Important gender differences in the proportion of those meeting nutrient guidelines were observed for 12 of the 18 nutrients examined, including carbohydrate; total, saturated, and monounsaturated fat; cholesterol; fiber; sodium; calcium; and several vitamins. CONCLUSIONS: Although progress has been made toward achieving population adherence to preventive nutrition recommendations, large proportions of adults fall short of guidelines for some key nutrients. Differences in adherence rates between men and women suggest areas for gender-specific, targeted nutrition messages and behavioral interventions.

Dietary patterns of men and women suggest targets for health promotion: the Framingham Nutrition Studies.

PURPOSE: The goal of the study was to characterize the dietary patterns of adult men and women. DESIGN: The study used a cross-sectional analysis of food consumption behaviors and nutrient intake measured from 1984 through 1988. SETTING: The Framingham Offspring/Spouse Study, Framingham, Massachusetts. SUBJECTS: The population-based sample comprised 1831 men and 1828 women between 20 and 70 years of age. MEASURES: Dietary patterns were defined by cluster analyses, which used the estimates of usual daily food intake from food frequency questionnaires, and the patterns were compared with Food Guide Pyramid recommendations. Nutrient intakes were independently estimated from 24-hour recalls and compared with Year 2000 nutrition recommendations. RESULTS: Cluster analyses identified five groups of men and five groups of women with distinctive dietary patterns. Men differed on intakes of all food groups except vegetables and snacks plus sweetened beverages. Specific dietary behaviors, including low intakes of whole grains, fruits, vegetables, and other complex carbohydrates; high intakes of beer and liquor; and high intakes of high-fat animal foods warrant targeted intervention messages for men. Women's patterns differed across all food groups except red meats and fattier poultry and beer. Dietary behaviors of women that deserve attention include low fruit, vegetable, starch, and dietary intakes; chronic dieting; high alcohol intake; and sources of hidden fats. No cluster met the current recommendations for food and nutrient intake. CONCLUSIONS: Distinct dietary patterns in Framingham men and women vary in compliance with national nutrition and health policy objectives and provide insights for developing behavioral interventions to improve food and nutrient intake.

Diet and plasma lipids in women. I. Macronutrients and plasma total and low-density lipoprotein cholesterol in women: the Framingham nutrition studies.

This study examined relationships between diet and plasma total and LDL cholesterol levels in a population-based sample of 695 premenopausal and 727 postmenopausal women participating in the Framingham Offspring/Spouse Study. Regression analyses controlled for age, caloric intake, apolipoprotein E isoform type, estrogen use, and important CVD risk factors indicated that plasma total and LDL-cholesterol levels were directly associated with consumption of saturated fat and inversely associated with total calorie intake. In contrast, dietary cholesterol was not a predictor of plasma total or LDL cholesterol levels. Total cholesterol levels were also directly associated with total fat, oleic acid, and animal fat, and inversely associated with carbohydrate intake. Stepwise regressions with key nutrients indicated that saturated fat was consistently associated with total and LDL cholesterol levels in Framingham women. These analyses suggest that diet explains 2% of the variability in these lipid levels in a cross-sectional sample of women; the full model explains 22-27%.

Diet and plasma lipids in women. II. Macronutrients and plasma triglycerides, high-density lipoprotein, and the ratio of total to high-density lipoprotein cholesterol in women: the Framingham nutrition studies.

This study examined relationships between macronutrients and plasma triglycerides, HDL, and the total-to-HDL cholesterol ratio (T/H ratio) in a population-based sample of 695 premenopausal and 727 postmenopausal women participating in the Framingham Offspring/Spouse Study. Multivariate regression analyses revealed that plasma triglycerides were inversely related to protein, fiber, and polyunsaturated fat and directly related to saturated fat and oleic acid. Alcohol intake was directly related to HDL cholesterol and inversely related to the T/H ratio in all subgroups of women, except for postmenopausal women with the 3/2 or 2/2 apolipoprotein E phenotype. Similarly, a direct relationship between dietary fat and HDL cholesterol was limited to this single subgroup of postmenopausal women. Since dietary fat and alcohol do not appear to have consistent effects on plasma lipids in all groups of women, it is important to consider the genetic contribution to diet/lipid relationships in epidemiological studies and when evaluating lipid-lowering interventions.

Secular trends in diet and risk factors for cardiovascular disease: the Framingham Study.

OBJECTIVE: In this study we examined changes in dietary intake and risk factors for cardiovascular disease that occurred over three decades in a US-population-based sample. DESIGN: Secular trends in dietary profiles and risk factors were studied in cross-sectional samples of subjects from the Framingham Study in 1957-1960, 1966-1969, and 1984-1988. RESULTS: Dietary levels of cholesterol appeared to have declined considerably, whereas macronutrient and fatty acid intakes appeared to change only slightly. Men appeared to increase their saturated fat intakes from 16.4% in 1966-1969 to 17.0% in 1984-1988 (P < .01). In spite of relatively stable mean total fat intake levels, 35% to 60% of Framingham Study men and women reported decreased consumption of higher-fat animal products over the 10-year period between 1974-1978 and 1984-1988. Framingham subjects who reported modifying their diets by substituting lower-fat foods for high-fat items between 1974-1978 and 1984-1988 were more likely to achieve the guidelines of the National Cholesterol Education Program and Healthy People 2000 for dietary fat and cholesterol intake and for serum total cholesterol level. Levels of systolic and diastolic blood pressure, total and low-density lipoprotein cholesterol, and cigarette smoking were also lower in 1984-1988 than in earlier times. Compared with 1957-1960, mean body mass index and prevalence rates of overweight and hypertension were higher in 1984-1988, despite higher levels of reported physical activity. CONCLUSIONS: The observed secular trends in diet and risk factor levels for cardiovascular disease in the Framingham population are important to guide the development and implementation of population-based strategies for promoting cardiovascular health, including nutrition interventions.

Use of focus groups to explore nutrition practices and health beliefs of urban Caribbean Latinos with diabetes.

OBJECTIVE: Although Caribbean Latinos are two to three times more likely than non-Hispanic whites to develop diabetes, cultural influences on nutrition and health are poorly understood. To provide insight into important features of diabetes prevention and management, we conducted focus groups to explore nutrition practices and health beliefs. RESEARCH DESIGN AND METHODS: Thirty low-income urban Caribbean Latinos with non-insulin-dependent diabetes mellitus (NIDDM) and four family members participated in four focus group interviews that were conducted in Boston and Cambridge, Massachusetts. Interviews were conducted in Spanish, were tape recorded, and were led and analyzed by Latino professionals from a community-based health organization. RESULTS: Consistent themes described by participants were feelings of social isolation, little understanding of long-term consequences of diabetes, fatalism regarding the course of the disease, multiple barriers to diet and exercise interventions, skepticism regarding the value of preventive health behaviors, prevalent use of traditional nonmedical remedies, and a clear need for culturally sensitive health-care providers and services. CONCLUSIONS: The information from focus groups provides useful information for planning innovative intervention programs for chronic disease risk reduction that emphasize practical skills development, family/peer networks, empowerment techniques, and bilingual providers. We conclude that the focus group technique can be used effectively with low-income, urban minority populations to provide information on lifestyle behaviors and beliefs regarding chronic diseases that impact on health and nutritional status.