Nutrient intake and peripheral artery disease in adults: key considerations in cross-sectional studies.
OBJECTIVE
There are limited studies of nutrient intake and peripheral artery disease (PAD). Some studies have not accounted for the functional consequences of PAD, potentially leading to biased results. To determine the associations between intakes of dietary fiber, folate, vitamins A, C, E, and B6 and PAD.


METHODS
Cross-sectional analysis of 6534 adults aged 40 years and older in the U.S. National Health and Nutrition Examination Survey between 1999 and 2004, including measurement of ankle-brachial index (ABI) and nutrient intake by 24-h dietary recall. Weighted multivariable logistic regression models to determine odds ratios and 95% confidence intervals.


RESULTS
The prevalence of PAD (ABI < 0.9) was 5.3% (4.7-5.9). Inverse associations between PAD and intakes of fiber, folate, and vitamins A, B6, C, and E were statistically significant when adjusting for age, sex, hypertension, diabetes and smoking. In models further adjusted for energy intake and physical activity, these odds ratios all became null (p ≥ 0.1).


CONCLUSIONS
In this sample, dietary fiber, folate, and vitamins B6, C, and E were not associated with PAD after accounting for energy intake and activity. Adjustment for energy and physical activity are essential to avoid bias due to reverse causation in cross-sectional studies of diet and PAD.
Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States. Electronic address: asghar_naqvi@hms.harvard.edu.
Asghar Z
AZ
Naqvi
Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; Harvard School of Public Health, Harvard Medical School, Boston, MA, United States. Electronic address: davis@hsph.harvard.edu.
Roger B
RB
Davis
Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; Harvard School of Public Health, Harvard Medical School, Boston, MA, United States. Electronic address: kmukamal@bidmc.harvard.edu.
Kenneth J
KJ
Mukamal
D000328:Adult; D000368:Aged; D055109:Ankle Brachial Index; D001205:Ascorbic Acid / Q000008:administration & dosage; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015930:Diet Records; D004043:Dietary Fiber / Q000008:administration & dosage; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D006801:Humans; D016015:Logistic Models; D008297:Male; D011939:Mental Recall; D018977:Micronutrients / Q000008:administration & dosage*; D008875:Middle Aged; D009043:Motor Activity; D015999:Multivariate Analysis; D009749:Nutrition Surveys; D058729:Peripheral Arterial Disease / Q000188:drug therapy* / Q000453:epidemiology*; D015995:Prevalence; D057185:Sedentary Behavior; D014801:Vitamin A / Q000008:administration & dosage; D025101:Vitamin B 6; D014810:Vitamin E / Q000008:administration & dosage
D004043:Dietary Fiber; D018977:Micronutrients; D014801:Vitamin A; D014810:Vitamin E; D025101:Vitamin B 6; D005492:Folic Acid; D001205:Ascorbic Acid
Activity; Cross-sectional; Diet; Energy; Nutrients; Peripheral artery disease