Silverstone et al. the homes of participants (October 2005– April 2007). The length of the interview was typically 45–60 min. Of the 1,110 individuals who completed the survey, 774 agreed to a clinic visit, which included measurements—by standard proto- col—of height, weight, waist circumference, and blood pressure, as well as a review of current medications. Fasting blood was obtained for analyses of glucose and lipids (Jacksonville Medical Center, Jacksonville, AL), the major 35 ortho-substituted PCB congeners, and 13 pesticides and herbicides [Division of Laboratory Sciences at the Centers for Disease Control and Prevention’s (CDC) National Center for Environmental Health, Atlanta, GA]. The PCB congeners and pesticides were measured in serum using high- resolutiongaschromatography/isotope-dilution Table 1. Participant characteristics and diabetes status: Anniston Community Health Survey. high-resolution mass spectrometry (Sjödin et al. 2004). Serum total lipids were calculated with the enzymatic summation method using triglyceride and total cholesterol measurements (Bernert et al. 2007). Total wet-weight levels of the 35 PCB congeners in nanograms per gram (parts per billion) were summed (ΣPCBs). Before summation, values below the limit of detection (LOD) were substituted with the congener- specific LOD divided by the square root of 2. The ΣPCB variable was divided into quintiles, with the first quintile serving as the referent category. Quintile limits were based on values from the entire group with PCB measurements. Because the PCB distribution showed a positive skew, a log-transformed version of the continuous wet-weight total PCB variable was derived for trend assessment Diabetes (n = 207) 58.7 ± 14.0 31.5 ± 19.9 639.1 ± 158.3 Total (n = 774) 54.8 ± 15.9 28.8 ± 19.3 633.3 ± 155.9 and for use in subgroup analyses. Consistent with recommendations from Schisterman et al. (2005), we evaluated both wet-weight PCB totals (nanograms per gram), with control for total lipids, and lipid-adjusted PCB values, but we report only the former here. Subsets of PCBs based on structure and function were summed (log-transformed) as follows: estrogenic congeners 44, 49, 66, 74, 99, 110, and 128 (DeCastro et al. 2006); mono-ortho congeners 28, 66, 74, 105, 118, 156, 157, 167, and 189; mono-ortho dioxin toxic equivalents (TEQ) 105, 118, 156, 157, 167, and 189 (Van den Berg et al. 2006); di-, tri-, and tetra- ortho congeners (combined) 44, 49, 52, 87, 99, 101, 110, 128, 138+158, 146, 153, 170, 172, 180, 194, 149, 151, 177, 178, 183, 187, 195, 196+203, 199, 206, and 209; and the ryanodine-like congeners 52, 101, 149, 151, 170, 180, 183, and 187 (activate ryanodine receptors at < 1 Mμ) (Pessah et al. 2006). In addition, we evaluated the possible association between log-transformed dichlorodiphenyl- dichloroethylene (DDE) and diabetes. For this study, diabetes was defined as self-report of physician-diagnosed diabetes or fasting glucose > 125 mg/dL. Prediabetes was defined as fasting glucose 100–125 mg/dL, absence of previously diagnosed diabetes, and absence of glycemic control medications. Normoglycemia was defined as individuals with a negative diabetes self-report, fasting glucose < 100 mg/dL, and the absence of glycemic control medications. Ever-smoking was defined as having smoked ≥ 100 ciga- rettes over a lifetime. A positive family his- tory of diabetes was defined as the presence of diabetes in siblings, parents, grandparents, aunts, or uncles. Participants were Caucasian (53%), African American (46%), and Native American (1%) and were grouped as white and nonwhite (African Americans, Native Americans) for purposes of these analyses. Laboratory results [glucose, total choles- terol, high-density lipoprotein (HDL), low- density lipoprotein (LDL), triglycerides, PCB, and pesticide levels] were available for 765 of the 774 participants. Demographic informa- tion was missing for < 3% of participants, with the exception of self-reported income (missing for 28%). Because individuals with missing data were excluded from the analy- ses, income was not included as a measure of socioeconomic status in multivariable models. Statistical analyses. Preliminary analyses included the calculation of frequencies, means, and SDs and the use of t-tests, one- way analysis of variance, general linear models (GLMs), and Pearson’s chi-square test. A GLM was used to calculate geometric means (GMs) using the antilog of the log-transformed PCB mean value adjusted for age, sex, race/ ethnicity, or body mass index (BMI) (Bland and Altman 1996). Unconditional logistic ovlume 120 | number 5 | May 2012 • Environmental Health Perspectives Characteristic Age (years)* No. of years in Anniston* Total lipids (mg/dL)* Sex* Female Male Race/ethnicitya* White Nonwhite Age (years)* 18–34 35–44 45–54 55–64 65–74 ≥ 75 BMI (kg/m2)* < 18.5 18.5–24.9 25.0–29.9 30.0–34.9 35.0–39.9 ≥ 40 Education Through grade 8 Some high school High school graduate Some college College graduate Smoker Never Ever Family history of diabetes* No Yes No Yes No Yes 728 Taking lipid-lowering medications* Self-reported heart diseaseb* Data are n (%) or mean ± SD. aOf the 363 nonwhites, 359 were African American and 4 were Native American. bAny self-reported heart disease includes a history of myocardial infarction, congestive heart failure or other heart disease. *p ≤ 0.05 in one-way ANOVA (means) or Pearson chi-square test, across all diabetes status categories. Normoglycemia (n = 396) 51.4 ± 16.8 27.3 ± 19.3 613.6 ± 138.3 287 (72) 109 (28) 226 (57) 170 (43) 69 (18) 67 (17) 84 (21) 82 (20) 56 (14) 38 (10) 5 (1) 122 (31) 106 (27) 87 (22) 39 (10) 36 (9) 37 (9) 76 (20) 157 (40) 85 (22) 36 (9) 185 (47) 211 (53) 165 (43) 219 (57) 339 (86) 57 (14) 316 (80) 77 (20) Diabetes status Prediabetes (n = 171) 57.6 ± 13.9 29.1 ± 18.5 671.6 ± 182.3 100 (59) 71 (41) 88 (52) 83 (48) 10 (6) 20 (12) 39 (23) 42 (25) 43 (25) 17 (9) 0 (0) 18 (10) 56 (33) 52 (31) 26 (15) 18 (11) 14 (8) 36 (21) 73 (43) 33 (19) 14 (8) 70 (41) 100 (59) 62 (38) 103 (62) 128 (75) 43 (25) 121 (71) 49 (29) 154 (74) 53 (26) 97 (47) 110 (53) 11 (5) 20 (10) 47 (23) 50 (24) 53 (26) 26 (12) 0 (0) 25 (12) 43 (21) 52 (25) 43 (21) 44 (21) 25 (12) 50 (24) 79 (38) 45 (22) 8 (4) 96 (47) 110 (53) 53 (26) 151 (74) 120 (58) 87 (42) 123 (60) 81 (40) 541 (70) 233 (30) 411 (53) 363 (47) 90 (12) 107 (14) 170 (22) 174 (22) 152 (20) 81 (10) 5 (< 1) 165 (21) 205 (27) 191 (25) 108 (14) 98 (13) 76 (10) 162 (21) 309 (40) 163 (21) 58 (8) 351 (45) 421 (55) 280 (37) 473 (63) 587 (76) 187 (24) 560 (73) 207 (27)