OBJECTIVES: Chronic inflammation is now thought to play a key pathogenetic role in the associations of obesity with insulin resistance and diabetes. Based on our recent findings on persistent organic pollutants (POPs) including the lack of an association between obesity and either insulin resistance or diabetes prevalence among subjects with very low concentrations of POPs, we hypothesized that POP concentrations may be associated with inflammation and modify the associations between inflammation and insulin resistance in non-diabetic subjects. METHODS: Cross-sectional associations among serum POPs, C-reactive protein (CRP), and homeostasis model assessment of insulin resistance (HOMA-IR) were investigated in 748 non-diabetic participants aged > or =20 years. Nineteen types of POPs in 5 subclasses were selected because the POPs were detectable in > or =60% of the participants. RESULTS: Among the five subclasses of POPs, only organochlorine (OC) pesticides showed positive associations with CRP concentrations, while polychlorinated biphenyls (PCBs) showed inverse associations with CRP concentrations. There were statistically significant interactions between CRP and OC pesticides and between CRP and PCBs, in estimating HOMA-IR (P for interaction <0.01 and <0.01, respectively). CRP was not associated with HOMA-IR among subjects with low concentrations of OC pesticides or PCBs, while CRP was strongly associated with HOMA-IR among subjects with high concentrations of these POPs. CONCLUSIONS: In the current study, OC pesticides were associated with increased levels of CRP, a marker of inflammation, and both OC pesticides and PCBs may also modify the associations between CRP and insulin resistance.
Adult ; C-Reactive Protein/analysis/*drug effects ; Environmental Pollutants/adverse effects/*blood ; Female ; Humans ; Hydrocarbons, Chlorinated/adverse effects/*blood ; Inflammation/*chemically induced ; Insulin Resistance/*physiology ; Male ; Middle Aged ; Nutrition Surveys ; Pesticides/adverse effects/blood ; Polychlorinated Biphenyls/adverse effects/*blood

There are substantial variations of relative risks (RR) in smoking-related mortality by country and time. We hypothesized the RRs in smoking-related mortality might differ depending on serum concentrations of persistent organic pollutants (POPs). We evaluated the associations of cigarette smoking with total mortality in 610 elderly (aged > or = 70 yr) (702 elderly for organochlorine pesticides [OCPs]) after stratification by serum concentration of POPs, in the National Health and Nutrition Examination Survey (NHANES) 1999-2004 followed through 2006. Summary measures of POPs subclasses showed significant or marginally significant interaction with cigarette smoking on the risk of total mortality. P values for interaction were 0.069 for polychlorinated dibenzo-p-dioxins (PCDDs), 0.008 for polychlorinated biphenyls (PCBs), and 0.024 for OCPs. The effect of smoking on total mortality showed different patterns according to the serum concentration of some POPs. Former or current smokers had 1.4 to 2.9 times higher mortality rates compared with never smokers among participants with higher serum concentrations of POPs (2nd or 3rd tertiles). However, when the level of PCBs or OCPs were low (1st tertile), there were little positive associations between smoking and mortality. Our study suggests that the background exposure to several POPs may be related to variability in smoking-related total mortality.
Aged ; Aged, 80 and over ; Environmental Exposure ; Environmental Pollutants/*blood ; Female ; Humans ; Hydrocarbons, Chlorinated/blood ; Male ; Nutrition Surveys ; Pesticides/blood ; Polychlorinated Biphenyls/blood ; Proportional Hazards Models ; Risk ; Smoking/*mortality ; Tetrachlorodibenzodioxin/analogs & derivatives/blood

There are substantial variations of relative risks (RR) in smoking-related mortality by country and time. We hypothesized the RRs in smoking-related mortality might differ depending on serum concentrations of persistent organic pollutants (POPs). We evaluated the associations of cigarette smoking with total mortality in 610 elderly (aged > or = 70 yr) (702 elderly for organochlorine pesticides [OCPs]) after stratification by serum concentration of POPs, in the National Health and Nutrition Examination Survey (NHANES) 1999-2004 followed through 2006. Summary measures of POPs subclasses showed significant or marginally significant interaction with cigarette smoking on the risk of total mortality. P values for interaction were 0.069 for polychlorinated dibenzo-p-dioxins (PCDDs), 0.008 for polychlorinated biphenyls (PCBs), and 0.024 for OCPs. The effect of smoking on total mortality showed different patterns according to the serum concentration of some POPs. Former or current smokers had 1.4 to 2.9 times higher mortality rates compared with never smokers among participants with higher serum concentrations of POPs (2nd or 3rd tertiles). However, when the level of PCBs or OCPs were low (1st tertile), there were little positive associations between smoking and mortality. Our study suggests that the background exposure to several POPs may be related to variability in smoking-related total mortality.
Aged ; Aged, 80 and over ; Environmental Exposure ; Environmental Pollutants/*blood ; Female ; Humans ; Hydrocarbons, Chlorinated/blood ; Male ; Nutrition Surveys ; Pesticides/blood ; Polychlorinated Biphenyls/blood ; Proportional Hazards Models ; Risk ; Smoking/*mortality ; Tetrachlorodibenzodioxin/analogs & derivatives/blood

Low-dose persistent organic pollutants (POPs), especially organochlorine pesticides (OCPs), have emerged as a new risk factor of many chronic diseases. As serum concentrations of POPs in humans are mainly determined by both their release from adipose tissue to circulation and their elimination from circulation, management of these internal pathways may be important in controlling the serum concentrations of POPs. As habitual physical activity can increase the elimination of POPs from circulation, we evaluated whether chronic physical activity is related to low serum POP concentrations.

OBJECTIVES: This study was performed to investigate if organochlorine pesticides (OCPs) were associated with metabolic syndrome and insulin resistance among non-diabetes. METHODS: Among subjects who participated in a community-based health survey, 50 non-diabetic subjects with metabolic syndrome and 50 normal controls were selected. Insulin resistance was measured by the homeostasis model assessment (HOMA-IR). Eight OCPs were selected. RESULTS: After adjusting for confounders except for body mass index (BMI), beta-hexachlorocyclohexane (beta-HCH) and heptachlor epoxide were positively associated with metabolic syndrome. Odds ratios across tertiles of beta-HCH and heptachlor epoxide were 1.0, 3.2 and 4.4, and 1.0, 4.0 and 6.0, respectively (p for trend = 0.01 and <0.01). After additional adjustment for body mass index (BMI), heptachlor epoxide still showed an increasing trend with adjusted odds ratios of 1.0, 4.1, and 4.6 (p for trend = 0.10). When the five components of metabolic syndrome (with the definition of high fasting glucose (> or =100 mg/dL)) were separately analyzed, all components were positively, but not significantly, associated with heptachlor epoxide. As the serum concentration of heptachlor epoxide increased, HOMA-IR increased significantly in subjects with metabolic syndrome even after adjusting for BMI (p value <0.05 and <0.01). CONCLUSIONS: Despite the small sample size, this study suggests that the background exposure to some OCPs may be associated with metabolic syndrome.