Department of Environmental Medicine, Institute of Public Health (C.A.G.T., L.I.R., C.D., P.G., F.N., T.K.J.), and Institute of Sports Science and Clinical Biomechanics (A.G., M.R.-L., L.B.A.), University of Southern Denmark, 5000 Odense C, Denmark; and Department of Biostatistics (K.D.S., T.S.), University of Copenhagen, 1353 Copenhagen, Denmark.
Our objective was to explore whether childhood exposure to perfluorinated and polyfluorinated compounds (PFCs), widely used stain- and grease-repellent chemicals, is associated with adiposity and markers of glycemic control.
Body mass index, skinfold thickness, waist circumference, leptin, adiponectin, insulin, glucose, and triglyceride concentrations were assessed in 8- to 10-year-old children in 1997 in a subset of the European Youth Heart Study, Danish component. Plasma PFC concentrations were available from 499 children. Linear regression models were performed to determine the association between PFC exposure and indicators of adiposity and markers of glycemic control.
There was no association between PFC exposures and adiposity or markers of glycemic control in normal-weight children. Among overweight children, an increase of 10 ng perfluorooctane sulfonic acid/mL plasma was associated with 16.2% (95% confidence interval [CI], 5.2%-28.3%) higher insulin concentration, 12.0% (95% CI, 2.4%-22.4%) higher ß-cell activity, 17.6% (95% CI, 5.8%-30.8%) higher insulin resistance, and 8.6% (95% CI, 1.2%-16.5%) higher triglyceride concentrations, and an increase of 10 ng perfluorooctanoic acid/mL plasma was associated with 71.6% (95% CI, 2.4%-187.5%) higher insulin concentration, 67.5% (95% CI, 5.5%-166.0%) higher ß-cell function, 73.9% (95% CI, 0.2%-202.0%) higher insulin resistance, and 76.2% (95% CI, 22.8%-153.0%) higher triglyceride concentrations.
Increased PFC exposure in overweight 8- to 10-year-old children was associated with higher insulin and triglyceride concentrations. Chance findings may explain some of our results, and due to the cross-sectional design, reverse causation cannot be excluded. The findings therefore need to be confirmed in longitudinal studies.
Department of Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark (JLT-P, HRA, PG, and TKJ); the Research Unit for Dietary Studies, Institute of Preventive Medicine, Copenhagen University Hospitals, Frederiksberg, Denmark (JLT-P and BLH); the National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark (BLH); the Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, Sydney, Australia (BLH); the Department of Occupational Medicine and Public Health, Tórshavn, Faroe Islands (US); and the Department of Environmental Medicine, Faroese Hospital System, Tórshavn, Faroe Islands (PW).
Chemicals with endocrine-disrupting abilities may act as obesogens and interfere with the body's natural weight-control mechanisms, especially if exposure occurs during prenatal life.
We examined the association between prenatal exposure to polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyldichloroethylene (DDE) and subsequent obesity at 5 and 7 y of age.
From 1997 to 2000, 656 pregnant Faroese women were recruited. PCB and DDE were measured in maternal serum and breast milk, and children's weight, height, and waist circumference (WC) were measured at clinical examinations at 5 and 7 y of age. The change in body mass index (BMI) from 5 to 7 y of age was calculated. Analyses were performed by using multiple linear regression models for girls and boys separately, taking into account maternal prepregnancy BMI.
For 7-y-old girls who had overweight mothers, PCB was associated with increased BMI (ß = 2.07, P = 0.007), and PCB and DDE were associated with an increased change in BMI from 5 to 7 y of age (PCB: ß = 1.23, P = 0.003; DDE: ß = 1.11, P = 0.008). No association was observed with BMI in girls with normal-weight mothers. PCB was associated with increased WC in girls with overweight mothers (ß = 2.48, P = 0.001) and normal-weight mothers (ß = 1.25, P = 0.04); DDE was associated with increased WC only in girls with overweight mothers (ß = 2.21, P = 0.002). No associations were observed between PCB or DDE and BMI in 5-y-old girls. For boys, no associations were observed.
Results suggest that prenatal exposure to PCB and DDE may play a role for subsequent obesity development. Girls whose mothers have a high prepregnancy BMI seem most affected.
Persistent organic pollutants (POPs) have metabolic disrupting abilities and are suggested to contribute to the obesity epidemic. We investigated whether serum concentrations of POPs at 8-10 years of age were associated with subsequent development of overweight at age 14-16 and 20-22 years.
The study was based on data from the European Youth Heart Study, Danish component (1997). Concentrations of several polychlorinated biphenyls (PCBs) and the organochlorine pesticides p,p-dichlorodiphenyldichloroethylene (DDE) and hexachlorobenzene (HCB) were measured in serum from children aged 8-10 years (n = 509). Information on BMI z-scores, waist circumference and % body fat were collected at clinical examinations at ages 8-10, 14-16 and 20-22 years. Multiple linear regression analyses were performed taking potential confounders into account.
Overall, POP serum concentrations were low: median SPCB 0.18 µg/g lipid, DDE 0.04 µg/g lipid and HCB 0.03 µg/g lipid. POPs were generally not associated with weight gain at 14-16 and 20-22 years of age, except for an inverse association among the highest exposed girls at 20-22 years of age, which might possibly be explained by multiple testing or residual confounding.
This study suggests that, in a low exposed population, childhood serum concentrations of PCB, DDE, and HCB are not associated with subsequent weight gain.
Saturated fat intake has been associated with both cardiovascular disease and cancer risk, and a newly published study found an association between saturated fat intake and a lower sperm concentration in infertile men.
The objective was to examine the association between dietary fat intake and semen quality among 701 young Danish men from the general population.
In this cross-sectional study, men were recruited when they were examined to determine their fitness for military service from 2008 to 2010. They delivered a semen sample, underwent a physical examination, and answered a questionnaire comprising a quantitative food-frequency questionnaire to assess food and nutrient intakes. Multiple linear regression analyses were performed with semen variables as outcomes and dietary fat intakes as exposure variables, adjusted for confounders.
A lower sperm concentration and total sperm count in men with a high intake of saturated fat was found. A significant dose-response association was found, and men in the highest quartile of saturated fat intake had a 38% (95% CI: 0.1%, 61%) lower sperm concentration and a 41% (95% CI: 4%, 64%) lower total sperm count than did men in the lowest quartile. No association between semen quality and intake of other types of fat was found.
Our findings are of potentially great public interest, because changes in diet over the past decades may be part of the explanation for the recently reported high frequency of subnormal human sperm counts. A reduction in saturated fat intake may be beneficial for both general and reproductive health.
Endocrine disrupting chemicals have been hypothesized to play a role in the obesity epidemic. Long-term effects of prenatal exposure to non-persistent pesticides on body composition have so far not been investigated. The purpose of this study was to assess possible effects of prenatal exposure to currently used pesticides on children's growth, endocrine and reproductive function.
In a prospective study of 247 children born by women working in greenhouses in early pregnancy, 168 were categorized as prenatally exposed to pesticides. At three months (n = 203) and at 6 to 11 years of age (n = 177) the children underwent a clinical examination and blood sampling for analysis of IGF-I, IGFBP3 and thyroid hormones. Body fat percentage at age 6 to 11 years was calculated from skin fold measurements. Pesticide related associations were tested by linear multiple regression analysis, adjusting for relevant confounders.
Compared to unexposed children birth weight and weight for gestational age were lower in the highly exposed children: -173 g (-322; -23), -4.8% (-9.0; -0.7) and medium exposed children: -139 g (-272; -6), -3.6% (-7.2; -0.0). Exposed (medium and highly together) children had significantly larger increase in BMI Z-score (0.55 SD (95% CI: 0.1; 1.0) from birth to school age) and highly exposed children had 15.8% (0.2; 34.6) larger skin folds and higher body fat percentage compared to unexposed. If prenatally exposed to both pesticides and maternal smoking (any amount), the sum of four skin folds was 46.9% (95% CI: 8.1; 99.5) and body fat percentage 29.1% (95% CI: 3.0; 61.4) higher. There were subtle associations between exposure and TSH Z-score -0.66(-1.287; -0.022) and IGF-I Z-score (girls: -0.62(-1.0; -0.22), boys: 0.38(-0.03; 0.79)), but not IGFBP3.
Occupational exposure to currently used pesticides may have adverse effects in spite of the added protection offered to pregnant women. Maternal exposure to combinations of modern, non-persistent pesticides during early pregnancy was associated with affected growth, both prenatally and postnatally. We found a biphasic association with lower weight at birth followed by increased body fat accumulation from birth to school age. We cannot rule out some residual confounding due to differences in social class, although this was adjusted for. Associations were stronger in highly exposed than in medium exposed children, and effects on body fat content at school age was potentiated by maternal smoking in pregnancy.
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Low serum T levels have been associated with type 2 diabetes (T2D) and cardiovascular disease. However, it is unresolved whether low T is a risk factor or rather a risk marker for these conditions.
The objective of the study was to investigate serum levels of total T, SHBG, free T, estradiol, LH, and FSH and the subsequent risk of T2D and/or cardiovascular disease.
A prospective cohort study consisting of 5350 men from the general population aged 30-70 years at baseline, examined between 1982 and 2001 and followed with complete registry follow-up until December 2011, ie, up to 29 years of follow-up.
T2D outcomes defined as the first diagnosis of T2D and cardiovascular outcomes defined as first diagnosis of either ischemic heart disease or stroke (ischemic and hemorrhagic stroke).
In Cox proportional hazards models, a significantly negative association between T quartile and the risk of T2D was seen. Similarly, men with SHBG in the highest quartile had a decreased risk of developing T2D (nonsmokers: hazard ratio 0.30, 95% confidence interval 0.14-0.63; smokers: hazard ratio 0.40, 95% confidence interval 0.20-0.78). Similar trends were seen for free T, however, insignificant in the fully adjusted analysis. No associations were seen for estradiol, LH, and FSH. A less consistent pattern was seen for the hormones in relation to CVD outcomes; nonsmoking men showed a pattern of higher levels of total T, SHBG, and LH being negatively associated with ischemic heart disease and less pronounced for stroke, whereas in smokers higher levels of total T, free T, and LH were positively associated with the two CVD outcomes.
The observed negative associations of T and SHBG with T2D, but no association to LH and free T, indicates that low T in men who develop T2D is a marker of the disease rather than primary hypogonadism being a causal risk factor.
Is parental age at delivery associated with a man's semen quality?
In this large register-based study both mother's and father's age are found to have minimal effects on semen quality in men.
Both maternal and paternal age have been associated with a range of adverse health effects in the offspring. Given the varied health effects of parental age upon offspring, and the sensitivity of genital development to external factors, it is plausible that the age of a man's mother and father at conception may impact his reproductive health. To our knowledge this is the first examination of the effects of parental age on semen quality.
A retrospective cohort study of 10 965 men with semen data and parental data.
The study was based on Danish men referred to the Copenhagen Sperm Analysis Laboratory due to infertility in their partnership. Men born from 1960 and delivering a semen sample until year 2000 were included. The men were linked to the Danish Civil Registration System to obtain information on parent's age at delivery. Logistic regression analyses were used to calculate odds ratios and 95% confidence intervals for impaired semen quality. Linear regression analyses were used to examine a relationship between semen parameters and paternal age.
There were no convincing effect of either mother's or father's age on a man's semen quality. As no trends were noted, the few statistically significant results are likely attributable to chance.
Information regarding individual subject characteristics which may impact sperm production (i.e. smoking, BMI) were not available. While our sample size was large, we cannot exclude the possibility that a trend may have been identified with a still larger sample. In addition, the Danish Civil Registration System is merely administrative and hence does not discriminate between biological and adopted children. However, the low rate of adoption (˜2%) suggests that misclassification would have a minimal impact. The men were all referred to the laboratory for infertility problems in their partnership and, therefore, do not represent the general population. We, however, compared semen quality among men within the cohort, and it is therefore less important whether they, in fact, represent the general population.
The current study found no link between parental age and a son's semen quality, suggesting other factors may explain recent impairments in men's reproductive health.
This work was supported by the Hans and Nora Buchard's Fund and the Kirsten and Freddy Johansen's Fund. No competing interests.
Human exposure to polychlorinated biphenyls (PCBs) has been associated to type 2 diabetes in adults.
We aimed to determine whether concurrent plasma PCB concentration was associated with markers of glucose metabolism in healthy children.
Cross-sectional study of 771 healthy Danish third grade school children ages 8-10 years in the municipality of Odense were recruited in 1997 through a two-stage cluster sampling from 25 schools stratified according to location and socioeconomic character; 509 (9.7 ? 0.8 y, 53% girls) had adequate amounts available for PCB analyses.
Fasting serum glucose and insulin were measured and a homeostasis assessment model of insulin resistance (HOMA-IR) and ?-cell function (HOMA-B) calculated. Plasma PCB congeners and other persistent compounds were measured and SPCB calculated.
PCBs were present in plasma at low concentrations, median, 0.19 ?g/g lipid (interquartile range, 0.12-0.31). After adjustment for putative confounding factors, the second, third, fourth, and fifth quintiles of total PCB were significantly inversely associated with serum insulin (-14.6%, -21.7%, -18.9%, -23.1%, P trend
Several persistent organochlorine pollutants (POPs) possess endocrine disrupting abilities, thereby potentially leading to an increased risk of obesity and metabolic diseases, especially if the exposure occurs during prenatal life. We have previously found associations between prenatal POP exposures and increased BMI, waist circumference and change in BMI from 5 to 7 years of age, though only among girls with overweight mothers.
In the same birth cohort, we investigated whether prenatal POP exposure was associated with serum concentrations of insulin and leptin among 5-year-old children, thus possibly mediating the association with overweight and obesity at 7 years of age.
The analyses were based on a prospective Faroese Birth Cohort (n=656), recruited between 1997 and 2000. Major POPs, polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyldichloroethylene (DDE) and hexachlorobenzene (HCB), were measured in maternal pregnancy serum and breast milk. Children were followed-up at the age of 5 years where a non-fasting blood sample was drawn; 520 children (273 boys and 247 girls) had adequate serum amounts available for biomarker analyses by Luminex® technology. Insulin and leptin concentrations were transformed from continuous to binary variables, using the 75th percentile as a cut-off point. Multiple logistic regression was used to investigate associations between prenatal POP exposures and non-fasting serum concentrations of insulin and leptin at age 5 while taking into account confounders.
Girls with highest prenatal POP exposure were more likely to have high non-fasting insulin levels (PCBs 4th quartile: OR=3.71; 95% CI: 1.36, 10.01. DDE 4th quartile: OR=2.75; 95% CI: 1.09, 6.90. HCB 4th quartile: OR=1.98; 95% CI: 1.06, 3.69) compared to girls in the lowest quartile. No significant associations were observed with leptin, or among boys. A mediating effect of insulin or leptin on later obesity was not observed.
These findings suggest, that for girls, prenatal exposure to POPs may play a role for later development of metabolic diseases by affecting the level of insulin.
Phthalates are used as plasticizers in soft polyvinyl chloride (PVC) and in a large number of consumer products. Because of reported health risks, diisononyl phthalate (DiNP) has been introduced as a replacement for di(2-ethylhexyl) phthalate (DEHP) in soft PVC. This raises concerns because animal data suggest that DiNP may have antiandrogenic properties similar to those of DEHP. The anogenital distance (AGD)--the distance from the anus to the genitals--has been used to assess reproductive toxicity.
The objective of this study was to examine the associations between prenatal phthalate exposure and AGD in Swedish infants.
AGD was measured in 196 boys at 21 months of age, and first-trimester urine was analyzed for 10 phthalate metabolites of DEP (diethyl phthalate), DBP (dibutyl phthalate), DEHP, BBzP (benzylbutyl phthalate), as well as DiNP and creatinine. Data on covariates were collected by questionnaires.
The most significant associations were found between the shorter of two AGD measures (anoscrotal distance; AGDas) and DiNP metabolites and strongest for oh-MMeOP [mono-(4-methyl-7-hydroxyloctyl) phthalate] and oxo-MMeOP [mono-(2-ethyl-5-oxohexyl) phthalate]. However, the AGDas reduction was small (4%) in relation to more than an interquartile range increase in DiNP exposure.
These findings call into question the safety of substituting DiNP for DEHP in soft PVC, particularly because a shorter male AGD has been shown to relate to male genital birth defects in children and impaired reproductive function in adult males and the fact that human levels of DiNP are increasing globally.
Cites: Int J Androl. 2010 Apr;33(2):317-2320132349