Aims: To elucidate the relationship between low circulating serum vitamin D levels and predisease conditions (ie, prediabetes and prehypertension) in healthy Mexican American adults.
Methods: Analyses were conducted using data from the United States National Health and Nutrition Examination Survey (NHANES) from 2001 through 2006. Free-living (ie, community-dwelling, nonimprisoned) adult Mexican American subjects (N = 788; men, n = 443; women, n = 345) who had provided written informed consent and had no history of diabetes, hypertension, dyslipidemia, metabolic syndrome, and/or cardiovascular disease were included in this report. Participants were not ingesting any prescription medications, nor did they exhibit any evidence of malabsorption. Participants were determined to be disease free.
Results: The mean serum vitamin D level for Mexican American adults (N = 788) of 50.5 nmol/L was significantly higher (P < 0.0001) than the mean of 35.9 nmol/L for non-Hispanic black adults (n = 621), and significantly lower (P < 0.0001) than the mean of 65.0 nmol/L for non-Hispanic white adults (n = 1711). Although age, sex, and body mass index were all significantly associated with prehypertension and prediabetes, no such association was found for serum vitamin D levels.
Conclusion: A successive, incremental shift of approximately 15 nmol/L in vitamin D distribution was seen in the transition from the dark-skinned non-Hispanic black population to the brown-skinned Mexican American population, and from the brown-skinned Mexican American population to the non-Hispanic white population. In contrast to the non-Hispanic black and non-Hispanic white populations, wherein previous studies found that serum vitamin D levels below the 75th percentile were associated with prediabetes and prehypertension, no such association was detected among the Mexican American population. The reason for this lack of association among the Mexican American population is unclear.