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.

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.