Relationship of Polyunsaturated Fatty Acid Intake to Peripheral Neuropathy Among Adults With Diabetes in the National Health and Nutrition Examination Survey (NHANES) 1999 –2004 MIN TAO, MD, PHD 1 MARGARET A. MCDOWELL, MPH, RD 2 SHARON H. SAYDAH, PHD 3 MARK S. EBERHARDT, PHD 3 OBJECTIVE — This study investigated the association between dietary intake of polyunsat- urated fatty acids (PUFAs) and peripheral neuropathy in the U.S. population. RESEARCH DESIGN AND METHODS — We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 1999 –2004 for adults 40 years of age with diagnosed diabetes, an assessment of peripheral neuropathy, and reliable 24-h dietary recall. The dietary intake of PUFAs was analyzed by peripheral neuropathy status. Multivariate logistic regression models were used to estimate the odds of having peripheral neuropathy in higher quintiles of PUFA intake compared with the lowest quintile. RESULTS — The mean dietary intake of linolenic acid was 1.25  0.07 g among adults with peripheral neuropathy, significantly lower than the 1.45  0.05 g intake among those without peripheral neuropathy. After controlling for potential confounding variables, adults whose lin- olenic acid intake was in the highest quintile had lower odds of peripheral neuropathy than adults in the lowest quintile (adjusted odds ratio 0.40 [95% CI 0.21– 0.77]). CONCLUSIONS — Among adults with diagnosed diabetes, dietary intake of linolenic acid is positively associated with lower odds of peripheral neuropathy. Diabetes Care 31:93–95, 2008 T he prevalence of peripheral neurop- athy is 28.5% among adults aged 40 years with diabetes in the U.S. population (1). Besides improving glyce- mic control, few available therapeutic choices for peripheral neuropathy can in- fluence its natural history (2). Identifica- tion of additional modifiable factors that may be related to the progression of pe- ripheral neuropathy is important. This study investigated whether dietary poly- unsaturated fatty acid (PUFA) intake is associated with measured peripheral neuropathy. RESEARCH DESIGN AND METHODS This study used data from the National Health and Nutrition Examination Survey (NHANES) 1999 –2004. The sample in- cludes 1,062 adults 40 years of age with self-reported diagnosed diabetes, periph- eral neuropathy measurement, and com- plete and reliable 24-h dietary recall data. Measurements of peripheral neuropathy Peripheral neuropathy was assessed by testing foot sensation using a 5.07-gauge Semmes-Weinstein nylon monofilament (3). Three plantar metatarsal sites (hallux and first and fifth metatarsal heads) were tested on each foot in random order. Pe- ripheral neuropathy was defined as hav- ing one or more insensate sites (1). Assessment of PUFA intake Dietary nutrient intake estimates were ob- tained from a single in-person interview of 24-h dietary intake. The NHANES data files include energy intake, total PUFA in- take, and intake of seven specific fatty ac- ids (C18:2, C18:3, C18:4, C20:4, C20:5, C22:5, and C22:6). Total long-chain PUFA intake was calculated by summing intake of PUFAs with 20 carbon atoms. Use of dietary supplements containing PUFA in the past 30 days was ascertained during the household interview (4). Covariates The analysis controlled for previously re- ported risk factors (5–7), namely self- reported age, sex, race/ethnicity, edu- cation, smoking status, duration of diabe- tes, and measured weight, height, blood pressure, and glycohemoglobin (A1C) (8,9). High blood pressure was defined as average systolic blood pressure 140 mmHg or average diastolic blood pres- sure 90 mmHg. Poor glycemic control was defined as A1C 7% (10). Statistics Descriptive statistics on the dietary intake of PUFAs and other characteristics were calculated. Student’s t test or  2 test was used separately for continuous or categor- ical variables. The percentages of adults with pe- ripheral neuropathy in each quintile of ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● From the 1 Epidemic Intelligence Service Program, Centers for Disease Control and Prevention, Hyattsville, Maryland; the 2 Division of Health and Nutrition Examination Surveys, National Center for Health Statistics, Hyattsville, Maryland; and the 3 Office of Analysis and Epidemiology, National Center for Health Statistics, Hyattsville, Maryland. Address correspondence and reprint requests to Mark Eberhardt, National Center for Health Statistics, Centers for Disease Control and Prevention, 3311 Toledo Rd., Hyattsville, MD 20782. E-mail: meberhardt@cdc.gov. Received for publication 2 June 2007 and accepted in revised form 1 October 2007. Published ahead of print at http//:care.diabetesjournals.org on 3 October 2007. DOI: 10.2337/dc07- 0931. Abbreviations: ALA, -linolenic acid; GLA, -linolenic acid; NHANES, National Health and Nutrition Examination Survey; PUFA, polyunsaturated fatty acid. A table elsewhere in this issue shows conventional and Syste `me International (SI) units and conversion factors for many substances. © 2008 by the American Diabetes Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Epidemiology/Health Services Research B R I E F R E P O R T DIABETES CARE, VOLUME 31, NUMBER 1, JANUARY 2008 93