ABSTRACT
INTRODUCTION: To examine factors potentially contributing to premature cardiovascular disease mortality in African Americans (40% versus 20% all other populations), plasma homocysteine, serum vitamin B12 and folate levels were examined for African American participants in the Jackson Heart Study. METHODS: Of 5192 African American Jackson Heart Study participants (21-94 years), 5064 (mean age, 55 ± 13 years; 63% female) had homocysteine levels measured via fasting blood samples, with further assessments of participants' vitamin B12 (n = 1790) and folate (n = 1788) levels. Regression analyses were used to examine age, gender, vitamin B12 and folate with homocysteine levels. RESULTS: Homocysteine levels, a purported surrogate risk factor for cardiovascular disease, increased with age, were inversely proportional to folate and vitamin B12 levels (P < 0.001) and were higher for men of all ages. CONCLUSIONS: The results show that, as with other populations, age, gender, vitamin B12 and folate may predict homocysteine levels for African Americans. Diet may be an important predictive factor as well, given the relationships that were observed between plasma homocysteine and serum B vitamin levels.
Subject(s)
Black or African American , Cardiovascular Diseases/ethnology , Folic Acid/blood , Homocysteine/blood , Vitamin B 12/blood , Adult , Age Factors , Aged , Aged, 80 and over , Cardiovascular Diseases/blood , Female , Humans , Linear Models , Male , Middle Aged , Mississippi , Sex Factors , Young AdultABSTRACT
OBJECTIVE: To examine the relative validity of two food frequency questionnaires (FFQs) developed for use in investigating diet and disease relationships within the adult African-American population in the southern United States. DESIGN: Cross-sectional analyses of dietary nutrient intake data, comparing four 24-hour dietary recalls with an FFQ developed by the Lower Mississippi Delta Nutrition Intervention Research Initiative, and its shorter version adapted for use in the Jackson Heart Study. SUBJECTS: A representative subset of participants (n=499, aged 35 to 81 years) from the baseline Jackson Heart Study cohort (N=5,302) was selected for this study. Data collection took place between winter 2000 and spring 2004. STATISTICAL ANALYSES: Pearson's correlation coefficients (energy adjusted and de-attenuated) for 26 nutrients estimates from each of the FFQs, comparing them with the mean of four 24-hour dietary recalls. The ability of the FFQs to rank individuals based on nutrient intakes was compared to that of the mean of four 24-hour dietary recalls and attenuation coefficients were also calculated. RESULTS: Median nutrient intake estimates tended to be higher on the long and lower on the short FFQ compared to the median for the mean of four 24-hour dietary recalls. Energy adjusted and deattenuated correlations of FFQ intake estimates with recalls ranged from 0.20 for sodium to 0.70 for carbohydrate for the short FFQ and from 0.23 for polyunsaturated fat to 0.75 for dietary fiber and magnesium for the long. Attenuation coefficients for men on average were 0.42 for the short and 0.49 for the long FFQ. For women, these were 0.31 for the short and 0.42 for the long FFQ. CONCLUSIONS: Both FFQs appear to be reasonably valid for assessment of dietary intake of adult African Americans in the South. The Lower Mississippi Delta Nutrition Intervention Research Initiative FFQ exhibited higher intake estimates and stronger correlations with recalls than the Jackson Heart Study FFQ for most nutrients analyzed, more so for women than men.
