Exposure to DDT and diabetic nephropathy among Mexican Americans in the 1999-2004 National Health and Nutrition Examination Survey.

Concentrations of the pesticide DDT (dichlorodiphenyltrichloroethane) and its metabolite DDE (dichlorodiphenyldichloroethylene), in the blood of Mexican Americans, were evaluated to determine their relationships with diabetes and diabetic nephropathy. The data were derived from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 (unweighted N = 1,411, population estimate = 13,760,609). The sample included teens, 12-19 years old, which accounted for 19.8% of the data. The time of the study overlapped the banning of DDT in Mexico in the year 2000, and those participants born in Mexico were exposed to DDT before they immigrated to the US. We sought to better understand the relationship of DDT with diabetes in a race/ethnicity group prone to develop diabetes and exposed to DDT. In this study, nephropathy was defined as urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria and macroalbuminuria, and total diabetes was defined as diagnosed and undiagnosed diabetes (glycohemoglobin, A1c ≥ 6.5%). The proportion with the isomer p,p'-DDT >0.086 ng/g (above the maximum limit of detection) was 13.3% for Mexican Americans born in the US, and 36.9% for those born in Mexico. Levels of p,p'-DDT >0.086 ng/g were associated with total diabetes with nephropathy (odds ratio = 4.42, 95% CI 2.23-8.76), and with total diabetes without nephropathy (odds ratio = 2.02, 95% CI 1.19-3.44). The third quartile of p,p'-DDE (2.99-7.67 ng/g) and the fourth quartile of p,p'-DDE (≥7.68 ng/g) were associated with diabetic nephropathy and had odds ratios of 5.32 (95% CI 1.05-26.87) and 14.95 (95% CI 2.96-75.48) compared to less than the median, respectively, whereas p,p'-DDE was not associated with total diabetes without nephropathy. The findings of this study differ from those of a prior investigation of the general adult US population in that there were more associations found with the Mexican Americans sample.

Association of dioxins, furans and dioxin-like PCBs in human blood with nephropathy among US teens and young adults.

We assessed the association of three chlorinated dibenzo-p-dioxins, a chlorinated dibenzofuran, and four dioxin-like polychlorinated biphenyls (PCBs) in human blood with nephropathy (microalbuminuria or macroalbuminuria) among teens and young adults (12-30 years old) having normal glycohemoglobin (A1c <5.7%). The data were derived from the 1999-2004 National Health and Nutrition Examination Survey (unweighted n=1504, population estimate=38,806,338). In this paper, nephropathy refers to normal A1c with nephropathy. In an all-adult sample (Everett CJ, Thompson OM. Dioxins, furans and dioxin-like PCBs in human blood: causes or consequences of diabetic nephropathy? Environ Res 2014;132:126-31), the cut-offs for these chemicals being considered elevated, were defined as the 75th percentile. Using these same cut-offs again, the proportion of those with one or more of the eight dioxin-like compounds elevated was 9.9%. The four chemicals associated with nephropathy were 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin, PCB 126, PCB 169, and PCB 156. The proportion with one or more of these four dioxin-like chemicals elevated was 3.9% (unweighted n=46) and the odds ratio (OR) for nephropathy was 7.1 [95% confidence interval (CI) 1.8-28.1]. The association was strong among females (OR 17.4, 95% CI 3.4-88.6), but among males there were no cases of nephropathy when one or more of the four dioxin-like chemicals were elevated, and therefore no association. In a separate analysis, elevated toxic equivalency, defined using the eight dioxin-like chemicals (TEQ8), was associated with nephropathy. TEQ8 ≥50.12 fg/g included 2.6% of the sample (unweighted n=28) and had an OR of 5.8 (95% 1.3-25.9) for nephropathy. As found in the analysis of one or more of four dioxin-like chemicals elevated, TEQ8 ≥50.12 fg/g was associated with nephropathy among females (OR 11.9, 95% CI 1.6-87.2), but not males. Trends for least-squares means also differed by gender, but there were no significant differences in mean TEQ8 between normal subjects and those having nephropathy in either males or females. We also evaluated pre-diabetes (A1c 5.7-6.4%) without nephropathy and found no associations when one or more of four dioxin-like compounds were elevated, or when TEQ8 was ≥50.12 fg/g. In this study, associations of dioxin-like chemicals with nephropathy were found among females at an early age. Prospective studies are needed to determine if dioxin-like compounds cause nephropathy, or if these relationships are cases of reverse causation.

Association of DDT and heptachlor epoxide in human blood with diabetic nephropathy.

Six organochlorine pesticides and pesticide metabolites in human blood were tested to determine their relationships with diabetic nephropathy. The data were derived from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 (unweighted, n=2992, population estimate=133,088,752). The six chemicals were p,p'-DDT (dichlorodiphenyltrichloroethane), p,p'-DDE (dichlorodiphenyltrichloroethylene), beta-hexachlorocyclohexane, oxychlordane, trans-nonachlor and heptachlor epoxide. In this research, total diabetes included diagnosed and undiagnosed diabetes (glycohemoglobin, A1c ≥6.5%), and nephropathy was defined as a urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria and macroalbuminuria. The pesticide p,p'-DDT and pesticide metabolite heptachlor epoxide were significantly associated with total diabetes with nephropathy, with odds ratios of 2.08 (95% CI 1.06-4.11) and 1.75 (95% CI 1.05-2.93), respectively. Organochlorine pesticides are thought to act through the constitutive androstane receptor/pregnane X receptor disease pathway, but this is not well established. When p,p'-DDT and heptachlor epoxide were both elevated, the odds ratio for diabetic nephropathy was 2.76 (95% CI 1.31-5.81), and when six of six organochlorine pesticides and pesticide metabolites, were elevated, the odds ratio for diabetic nephropathy was 3.00 (95% CI 1.08-8.36). The differences in the odds ratios for these groups appear to be due to differences in the mean heptachlor epoxide concentration of each category. Organochlorine pesticides and pesticide metabolites are known to have estrogenic, antiestrogenic or antiandrogenic activity. The constitutive androstane receptor/pregnane X receptor pathway is thought to interact with the aryl hydrocarbon receptor pathway, and the associations noted may be due to that interaction.

Dioxins, furans and dioxin-like PCBs in human blood: causes or consequences of diabetic nephropathy?

Nephropathy, or kidney disease, is a major, potential complication of diabetes. We assessed the association of 6 chlorinated dibenzo-p-dioxins, 9 chlorinated dibenzofurans and 8 polychlorinated biphenyls (PCBs) in blood with diabetic nephropathy in the 1999-2004 National Health and Nutrition Examination Survey (unweighted N=2588, population estimate=117,658,357). Diabetes was defined as diagnosed or undiagnosed (glycohemoglobin ≥ 6.5%) and nephropathy defined as urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria or macroalbuminuria. For the 8 chemicals analyzed separately, values above the 75th percentile were considered elevated, whereas for the other 15 compounds values above the maximum limit of detection were considered elevated. Seven of 8 dioxins and dioxin-like compounds, analyzed separately, were found to be associated with diabetic nephropathy. The chemicals associated with diabetic nephropathy were: 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin; 2,3,4,7,8-Pentachlorodibenzofuran; PCB 126; PCB 169; PCB 118; and PCB 156. Three of the 8 dioxins and dioxin-like compounds; 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin; 2,3,4,7,8-Pentachlorodibenzofuran and PCB 118; expressed as log-transformed continuous variables; were associated with diabetes without nephropathy. When 4 or more of the 23 chemicals were elevated the odds ratios were 7.00 (95% CI=1.80-27.20) for diabetic nephropathy and 2.13 (95% CI=0.95-4.78) for diabetes without nephropathy. Log-transformed toxic equivalency (TEQ) was associated with both diabetic nephropathy, and diabetes without nephropathy, the odds ratios were 2.35 (95% CI=1.57-3.52) for diabetic nephropathy, and 1.44 (95% CI=1.11-1.87) for diabetes without nephropathy. As the kidneys function to remove waste products from the blood, diabetic nephropathy could be either the cause or the consequence (or both) of exposure to dioxins, furans and dioxin-like PCBs.

Evaluation of three short dietary instruments to assess fruit and vegetable intake: the National Cancer Institute's food attitudes and behaviors survey.

BACKGROUND: Fruit and vegetable (F/V) intake assessment tools that are valid, reliable, brief, and easy to administer and code are vital to the field of public health nutrition. OBJECTIVE: To evaluate three short F/V intake screeners (ie, a 2-item serving tool, a 2-item cup tool, and a 16-item F/V intake screener) among adults using multiple 24-hour dietary recalls (24-hour recalls) as the reference instrument and evaluate test-retest reliability of the screeners across a 2- to 3-week time period. DESIGN: Validity and reliability study. PARTICIPANTS/SETTING: Two hundred forty-four adults for the validity study and 335 adults for test-retest reliability. STATISTICAL ANALYSES PERFORMED: Median values for F/V intakes were calculated for the screeners and 24-hour recalls. The Wilcoxon signed rank test was used to compare screeners with the 24-hour recalls. Deattenuated Pearson correlations were reported for validity and intraclass correlation coefficient used for reliability. RESULTS: The estimated median daily servings/cups of F/V for the 2-item serving screener was lower, for the 2-item cup screener was equivalent for men but higher for women, and for the 16-item F/V intake screener were about the same when compared with 24-hour recall values. The deattenuated correlations comparing the 24-hour recalls with the screeners were positive but weak for the 2-item serving screener, and were positive and moderate in strength for the 2-item cup and 16-item F/V intake screeners. The test-retest intraclass correlation coefficients were all positive and fairly strong for all of the screeners. CONCLUSIONS: Although dietary screeners offer a more cost-effective, less burdensome way to obtain gross estimates to rank individuals with regard to F/V intake, these methods are not recommended for assessing precise intake levels.

Associations of dioxins, furans and dioxin-like PCBs with diabetes and pre-diabetes: is the toxic equivalency approach useful?

Toxic equivalency factors for dioxins and dioxin-like compounds have been established by the World Health Organization. Toxic equivalency (TEQ) was derived using 6 chlorinated dibenzo-p-dioxins, 9 chlorinated dibenzofurans and 8 polychlorinated biphenyls, in blood, from the 1999-2004 National Health and Nutrition Examination Survey. Relationships of 8 individual chemicals, the number of compounds elevated, and TEQ with pre-diabetes and total diabetes (diagnosed and undiagnosed) were investigated using logistic regressions. For the 8 chemicals analyzed separately, values above the 75th percentile were considered elevated, whereas for the other 15 compounds, values above the maximum limit of detection were considered elevated. Pre-diabetes with glycohemoglobin (A1c) 5.9-6.4% was associated with PCB 126, PCB 118 and having one or more compounds elevated (odds ratio 2.47, 95% CI 1.51-4.06). Pre-diabetes with A1c 5.7-5.8% was not associated with any individual chemical or the number of compounds elevated. Total diabetes was associated with 6 of the 8 individual compounds tested, and was associated with having 4 or more compounds elevated. Toxic equivalency ≥81.58 TEQ fg/g was associated with total diabetes (odds ratio 3.08, 95% CI 1.20-7.90), but was not associated with A1c 5.9-6.4%. Having multiple compounds elevated appeared to be important for total diabetes, whereas for pre-diabetes with A1c 5.9-6.4%, having a single compound elevated appeared most important. Diabetes plus A1c ≥5.9% was associated with 34.16-81.57 TEQ fg/g (odds ratio 2.00, 95% CI 1.06-3.77) and with ≥81.58 TEQ fg/g (odds ratio 2.48, 95% CI 1.21-5.11), indicating that half the population has elevated risk for this combination of conditions.

Fruit and vegetable intake of US adults: comparing intake by mode of survey administration.

Modes for collecting dietary data vary across studies and include in-person/interviewer-administered surveys, mail, and telephone surveys. Few studies use mixed modes to assess dietary intakes. Using data from the 2007 Health Information National Trends Survey, we compared fruit and vegetable intake of adults measured through dual modes (mail and random-digit dial [RDD] telephone), and discussed potential factors that could account for mode differences. The Health Information National Trends Survey data were collected through mailed (n=3,582), and RDD (n=4,092) surveys from December 2007 to May 2008. Data were weighted and analyzed in SUDAAN. Unadjusted mean fruit and vegetable intake was 0.48 servings higher (P<0.001) among mail (mean 5.40) vs RDD (mean 4.09) participants. In a multivariate model that controlled for other predictors, the odds of consuming ≥5 servings of fruit and vegetables per day was 83% higher among mail respondents compared to RDD (odds ratio 1.83, 95% confidence interval 1.62 to 2.07). Other predictors of fruit and vegetable intake were sex, education, participation in physical activity, self-rated health, and knowledge of the fruit and vegetable recommendation. Methodologic issues may account for modal differences in fruit and vegetable intake. Different measures (cups, servings) were used to assess fruit and vegetable intake in both modes, details about portion sizes were provided on the mail mode vs RDD, and closed-ended responses were provided on the mail vs open-ended responses for RDD. We cannot recommend one mode over the other nor attribute mode differences to real differences in reported fruit and vegetable intake between participants from both modes. Future research that uses dual modes needs to use identical methods of dietary assessment to minimize these potential sources of error. Further research is needed to validate the use of dual modes to assess dietary intake and inform research practice.

Improving fruit and vegetable consumption: use of farm-to-consumer venues among US adults.

Improvements to the food environment including new store development and more farm-to-consumer approaches (ie, farmers' markets, roadside stands, pick-your-own produce farms, or community-supported agriculture programs) may aid Americans in making healthier dietary choices. We analyzed data from a subset of respondents (N = 1,994) in the National Cancer Institute's Food Attitudes and Behaviors Survey, a mail survey of US adults. We determined associations between primary grocery shoppers' region and sociodemographic characteristics and frequency of purchasing fruits and vegetables in the summer from farm-to-consumer venues. A little more than one-quarter (27%) of grocery shoppers reported a frequency of at least weekly use of farm-to-consumer approaches. Older adults and respondents who live in the Northeast were most likely to shop farm-to-consumer venues at least weekly, and no differences were found by sex, race/ethnicity, education, or annual household income. These findings suggest that farm-to-consumer venues are used by many Americans and could be expanded to increase access to fruits and vegetables.

The meaning of 'fruits' and 'vegetables'.

OBJECTIVE: Fruit and vegetable consumption is a focus of research and nutrition education; yet, there is no universal agreement on the meaning of 'fruits' and 'vegetables'. Our objective was to describe survey respondent perceptions about a set of foods with regard to whether the food is a fruit, vegetable or something else. DESIGN: Three cross-sectional studies. SETTING: Two small studies involving cognitive interviewing sessions; and one large self-administered population survey. SUBJECTS: US adults in two small studies (n 55 and 80) and one large survey (n 3312), all with multiple race/ethnicities. RESULTS: Perceptions varied. In the survey, rice was considered a vegetable by about 20 % of respondents. In one small study, Spanish speakers were more likely to consider rice a vegetable, and Chinese speakers less likely, than were English speakers. Black beans were frequently classified as something other than vegetable or fruit. Among Hispanics, Spanish speakers were less likely than English speakers to consider beans a vegetable. Overall, tomatoes were classified as both fruit and vegetable, and these perceptions varied by race/ethnicity. CONCLUSIONS: Substantial disagreement among the fruit, vegetable and other food domains highlights the importance of clearly defining the desired constructs. Foods that require specific instruction include rice, dried beans, potatoes, tomatoes and fruits and vegetables in mixtures and condiments. For measurement, additional questions or explanations may be needed to clarify which foods are of interest. For communication, the global message to increase consumption of fruit and vegetables should be reinforced with specific guidance.

Knowledge of and adherence to fruit and vegetable recommendations and intakes: results of the 2003 health information national trends survey.

Attention to cancer-relevant communication (e.g., fruit/vegetable intake recommendations) through various media has been shown to be a pivotal step in reduction of the cancer burden, thus underscoring the importance of examining associations between exposure to health media and knowledge of and adherence to fruit/vegetable intake recommendations. The purpose of the present study was to assess factors associated with fruit/vegetable intake knowledge and behavior. The authors analyzed data collected from the 2003 Health Information National Trends Survey to evaluate the effect of fruit/vegetable intake knowledge on behavior, and the relationship of this effect with biobehavioral, sociodemographic, and communication characteristics. Participants who were knowledgeable of fruit/vegetable intake recommendations and consumed at least 5 fruit/vegetable servings per day were classified as informed compliers. Associations were observed for being an informed complier and paying "a lot" of attention to health media on the radio, in the newspaper, and in magazines and "a little" or "some" attention to health media in magazines or on the Internet. The recent explosion of available cancer-related information through various media underscores the importance of examining associations between exposure to health media and knowledge of and adherence to fruit/vegetable intake recommendations.

School vending machine purchasing behavior: results from the 2005 YouthStyles survey.

BACKGROUND: Competitive foods are often available in school vending machines. Providing youth with access to school vending machines, and thus competitive foods, is of concern, considering the continued high prevalence of childhood obesity: competitive foods tend to be energy dense and nutrient poor and can contribute to increased energy intake in children and adolescents. METHODS: To evaluate the relationship between school vending machine purchasing behavior and school vending machine access and individual-level dietary characteristics, we used population-level YouthStyles 2005 survey data to compare nutrition-related policy and behavioral characteristics by the number of weekly vending machine purchases made by public school children and adolescents (N = 869). Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed using age- and race/ethnicity-adjusted logistic regression models that were weighted on age and sex of child, annual household income, head of household age, and race/ethnicity of the adult in study. Data were collected in 2005 and analyzed in 2008. RESULTS: Compared to participants who did not purchase from a vending machine, participants who purchased >or=3 days/week were more likely to (1) have unrestricted access to a school vending machine (OR = 1.71; 95% CI = 1.13-2.59); (2) consume regular soda and chocolate candy >or=1 time/day (OR = 3.21; 95% CI = 1.87-5.51 and OR = 2.71; 95% CI = 1.34-5.46, respectively); and (3) purchase pizza or fried foods from a school cafeteria >or=1 day/week (OR = 5.05; 95% CI = 3.10-8.22). CONCLUSIONS: Future studies are needed to establish the contribution that the school-nutrition environment makes on overall youth dietary intake behavior, paying special attention to health disparities between whites and nonwhites.

Serum leptin and adiponectin levels and risk of Barrett's esophagus and intestinal metaplasia of the gastroesophageal junction.

Persons diagnosed with Barrett's esophagus (BE) are at increased risk of developing esophageal adenocarcinoma (EA). Obesity is a major risk factor for both BE and EA. The primary purposes of this study were to determine whether circulating levels of leptin and adiponectin, both of which are deregulated in obese states, predict risk of specialized intestinal metaplasia (SIM) occurring in the esophagus (BE) and/or gastroesophageal junction, and evaluate the extent to which they mediate the relationship between obesity and these conditions. In this case-control study, 177 persons newly diagnosed with SIM were compared with 173 general population controls using unconditional logistic regression. Females in the highest tertiles of BMI and waist circumference were at the greatest risk (adjusted odds ratio (OR) = 4.6 (95% confidence interval (CI) = 1.9, 11.6), P(trend) = 0.002; OR = 5.1 (95% CI = 2.0, 13.0), P(trend) = 0.002, respectively) compared to females in the lowest tertiles. Adjustment for leptin and adiponectin attenuated these associations by 52 and 42%, respectively. Males in the highest tertile of waist-to-hip ratio were at the greatest risk (adjusted OR = 2.8 (95% CI = 1.3, 5.9), P(trend) = 0.014) compared to males in the lowest tertile. However, adjustment for leptin and adiponectin did not attenuate these associations. Our study results are consistent with the notion that circulating leptin and adiponectin partially mediate the obesity-BE relationship in women. Leptin and adiponectin's role in the progression from normal epithelium to SIM/BE and on to EA should be further elucidated.

Vegetable and fruit intakes and risk of Barrett's esophagus in men and women.

BACKGROUND: Barrett's esophagus (BE) is a risk factor for esophageal adenocarcinoma. Modifiable risk factors for BE are largely unknown. OBJECTIVE: The purpose of this study was to determine whether vegetable and fruit intakes are associated with BE risk. DESIGN: In a case-control study based in western Washington State, we compared the vegetable and fruit intakes of 170 patients with newly diagnosed BE with those of 182 controls from the general population. Relations between vegetable and fruit intakes and BE were examined by using unconditional logistic regression to compute odds ratios (ORs) and corresponding 95% CIs. RESULTS: Participants in the second (adjusted OR: 0.40; 95% CI: 0.23, 0.71) and third (adjusted OR: 0.33; 95% CI: 0.17, 0.63) tertiles of vegetable intake appeared to have a lower risk of BE (P for trend = 0.048) than did participants in the first tertile of vegetable intake. Similarly, participants in the second (adjusted OR: 0.49; 95% CI: 0.28, 0.86) and third (adjusted OR: 0.39; 95% CI: 0.21, 0.75) tertiles of combined vegetable and fruit intakes had a lower risk of BE (P for trend = 0.047) than did participants in the first tertile of vegetable and fruit intakes. Similar results were obtained in subanalyses limited to patients with visible and with long-segment BE. CONCLUSIONS: The results support previous findings that increased intakes of vegetables and of vegetables and fruit are associated with a lower risk of BE in men and women. Prospective data that examine relations between diet and BE are needed.