AIMS/HYPOTHESIS: Dietary fatty acids may affect insulin sensitivity. Adipose tissue fatty acid composition partly reflects long-term dietary intake, but data from large studies regarding relationships with insulin sensitivity are lacking. We aimed to determine the association between adipose tissue fatty acids and insulin sensitivity in elderly Swedish men. METHODS: In a cross-sectional analysis of the community-based Uppsala Longitudinal Study of Adult Men (n = 795, mean age 71 years), adipose tissue biopsies were obtained and fatty acid composition was determined by gas-liquid chromatography. Insulin sensitivity was measured directly by a euglycaemic clamp. RESULTS: Palmitic acid (16:0), the major saturated fatty acid (SFA) in the diet and in adipose tissue, was negatively correlated with insulin sensitivity (r = -0.14), as were 16:1 n-7 (r = -0.15), 20:3 n-6 (r = -0.31), 20:4 n-6 (r = -0.38), 22:4 n-6 (r = -0.37) and 22:5 n-3 (r = -0.24; p
The objective of the study is to estimate the exposure to pyrene, an indicator of polycyclic aromatic hydrocarbons (PAHs) in the general environment, by using the internal dose of 1-hydroxypyrene (1-OHP) among people living nearby an aluminium smelter in the Montérégie area, Province of Québec, Canada.
This cross-sectional study was done in November and December 1998. Participants were randomly selected according to their environmental exposure to PAHs and were distributed according to three exposure levels (high, low, none). Altogether, 121 non smokers aged between 18 to 70 years were recruited for the study. Persons occupationally exposed to PAHs or using tar-based medications were excluded. Those with personal medical conditions that affect the metabolism of pyrene were also excluded. Urine samples were taken in the morning and analysed by gas chromatography and mass spectrometry (GC-MS) to determine the concentration of the metabolite, 1-OHP.
Among the exposed group (n=78), the geometric mean of urinary concentration of 1-OHP was 0.073 micromol/mol creatinine compared to 0.060 micromol/mol creatinine for the control group (n=40). The difference did not reach statistical significance (p=0.09). Geometric means among the three groups of exposure (high, low, none) were respectively 0.079, 0.067 and 0.060 micromol/mol creatinine (p=0.13). Accounting for personal risk factors, such as diet, passive smoke, use of wood heating and time spent at home during the three days prior to urine sampling, did not change previous results.
This study indicates that the environmental levels of PAH produced by this factory are low and do not contribute significantly to the body burden of PAH as measured by 1-OHP.
BACKGROUND: Carbon monoxide (CO) is normally present in the human body due to endogenous production of CO. CO can also be inhaled by exposure to external sources such as cigarette smoke, car exhaust, and fire. The purpose of this study was to investigate CO concentrations in blood from 410 blood donors at the blood center in Umeå, Sweden. To further evaluate the effects of cigarette smoking on CO concentrations, the elimination time for CO was examined in six volunteer smokers after a smoked cigarette. STUDY DESIGN AND METHODS: Blood samples from whole blood donors were obtained during the blood center's routine operation. In connection with blood donations, demographic and behavioral data were collected from the donors. The CO concentration was determined using gas chromatography. RESULTS: The majority of blood donors had approximately the same CO concentration (mean, 84.5 micromol/L). In 6 percent of the samples, the concentrations were higher than 130 micromol per L. The highest CO concentration was 561 micromol per L. The main source for these high CO concentrations appeared to be cigarette smoking. In the volunteer smokers, the elimination time after a smoked cigarette varied significantly, with elimination half-lives from 4.7 to 8.4 hours. CONCLUSION: These results show that blood bank red blood cell bags may have CO concentrations above the physiologic level. The time interval between cigarette smoking and blood donation seems to be a particularly important factor for elevated CO concentrations.
We conducted a first pilot study on healthy women living in two countries with different dietary habits, Granada in the south of Spain and Malmö in the south of Sweden, in order to compare their levels of plasma phospholipid fatty acids, and to examine the relationship between the differences in food consumption. This study is part of a pilot study which is nested in the European Prospective Investigation into Cancer and Nutrition, a multi-centre prospective cohort study on diet, plasma concentrations of antioxidants and fatty acids, and markers of oxidative stress. Thirty-nine women in Granada and thirty-eight women in Malmö, aged 45-50 years (all pre-menopausal) were selected among the female participants in the cohorts from these two countries. Individual measurements of the women's habitual diet were obtained by a food frequency questionnaire. 24-hour diet recalls were used for the standardised measurement of diet at group level. Plasma phospholipid fatty acid composition was determined by capillary gas chromatography. We found a different fatty acid profile in plasma between the two populations, with higher mean levels of palmitic acid (16:0), palmitoleic acid (16:1) (n-7), oleic acid (18:1), alpha-linolenic acid (18:3) (n-3) and eicosapentaenoic acid (20:5) (n-3), and lower mean levels of stearic acid (18:0) in Malmö compared to Granada. Women in Malmö consumed more meat, alcoholic beverages and sugar, and less fish and shellfish than women in Granada. We conclude that the fatty acid composition in plasma phospholipids is different between women from the two European centres. For polyunsaturated fatty acids, differences were observed for (n-3) fatty acids. In relation to these differences, we observed that specific food intakes, particularly meat and fish, varied between the two centres.
BACKGROUND: Objective validation of smoking status is necessary. Earlier studies have used saliva cotinine concentrations between 14.2 and 30 ng/ml as cut-off values to distinguish pregnant smokers from non-smokers. However, these cut-offs derive from studies including men and non-pregnant women. This constitutes a problem, as recent studies have reported an accelerated metabolism in pregnant smokers. The aim of this study was to determine the optimum cut-off cotinine level distinguishing pregnant smokers from pregnant non-smokers. METHODS: An observational study of 620 pregnant women, 359 self-reported smokers and 261 self-reported non-smokers, with complete data on smoking status and saliva cotinine. The study was conducted at a large university hospital in Copenhagen, Denmark. Saliva was sampled at the first antenatal visit to the midwife and analyzed for cotinine level by gas chromatography. Participants completed a questionnaire immediately after the first visit. RESULTS: A saliva cotinine cut-off level of 13 ng/ml, corresponding to a sensitivity of 0.99 and specificity 0.98, was found to be the optimum cut-off value separating pregnant smokers from non-smokers. The sum of the sensitivity and specificity was at its maximum, 1.981. A 95% bootstrap confidence interval for the optimum cut-off was (8-14 ng/ml). CONCLUSION: From the present data we recommend that in future studies on smoking cessation and pregnancy a cut-off level of 13 ng/ml should be applied to distinguish between pregnant smokers and non-smokers.
The nicotine concentration in samples of house dust from the homes of 34 smokers and 38 nonsmokers was analyzed using a gas chromatographic method. A strong positive correlation (r = .65, p less than .0001) between the amount smoked and the nicotine concentration in the house dust was found when the results from all homes were analyzed, and a fairly strong positive correlation (r = .35, p less than .05) was found for smokers' homes only. These data suggest that the nonsmoker may inhale tobacco constituents from respirable dust, even if smoking does not occur. The amount of nicotine inhaled during 1 h was estimated for someone in one of the homes where there was a high nicotine concentration in the house dust. The calculated amount, 12 ng, is very small compared with the amount inhaled when active smoking occurs (i.e., 600-3,000 ng/h). In this study, nicotine was a marker of tobacco pollution. Assuming that other tobacco smoke agents have a similar or smaller affinity to house dust as that of nicotine, we conclude that house dust inhalation constitutes only a modest additional source of involuntary smoking.
Inuit from Nunavik (northern Quebec) consume large amounts of fish and marine mammals, which are important sources of n-3 polyunsaturated fatty acids (n-3 PUFAs). These substances have a beneficial impact on heart rate (HR) and heart rate variability (HRV). However, it is unknown if this beneficial impact remains significant in populations with high mercury exposure. The study assessed the impact of n-3 PUFAs (Docosahexaenoic [DHA] and Eicosapentaenoic acid [EPA]) on resting HR and HRV among Nunavik Inuit adults considering mercury and other potential confounders.
Cross-sectional study employing clinical measurements.
Complete data were collected among 181 adults = 40 years old (109 women and 72 men) living in the 14 coastal villages of Nunavik. Several indices of HRV were derived from a 2-hour Holter monitoring assessment. n-3 PUFAs levels were measured in membrane erythrocytes. Simple linear regression was used to analyse the relationship between n-3 PUFAs levels and resting HR and HRV parameters while multiple linear regressions were carried out to control for confounders.
In the overall analyses, EPA was associated with SDANN (ß = 0.07, p = 0.04) and LF norm (ß = -1.84, p = 0.03) after adjusting for confounders. Among women, DHA was associated with resting HR (ß =-1.40, p = 0.03) while EPA was associated with SDNN (ß = 0.08, p = 0.03), SDANN (ß = 0.09, p = 0.02) and resting HR (ß = -2.61, p = 0.002). No significant association was observed in men.
These results suggest a beneficial impact of n-3 PUFAs on resting HR and HRV among Nunavik Inuit women.
Conjugated linoleic acid (CLA) is anticarcinogenic in experimental animal studies. We studied dietary and serum CLA in Finnish patients with breast cancer in 1992-1995. Participants were consecutive women with breast cancer (68 premenopausal and 127 postmenopausal) and population-based control women (75 premenopausal and 133 postmenopausal), matched for age and area of residence. Diet was assessed by a validated food frequency questionnaire and the fatty acid composition of serum by gas-liquid chromatography. In postmenopausal women, dietary CLA, serum CLA, myristic acid, and trans-vaccenic acid were significantly lower in cases than in controls. The odds ratio for breast cancer in the highest quintile vs. the lowest was 0.4 [95% confidence interval (CI) = 0.2-0.9]for CLA, 0.3 (95% CI = 0.1-0.7) for myristic acid, and 0.3 (95% CI = 0.1-0.7) for trans-vaccenic acid in serum. The odds ratios remained similar after adjustment for known risk factors of breast cancer. A diet composed of CLA-rich foods, particularly cheese, may protect against breast cancer in postmenopausal women, but it is impossible to assess the independent effects of CLA in this study. The findings may be of relevance for food production, inasmuch as it is possible to increase CLA and its precursor trans-vaccenic acid in foods by modifying the feeding of ruminants.
Intakes of omega-3 (n-3) fatty acids (FA) are associated with several health benefits. The aim of this study was to verify whether intakes of n-3 FA estimated from a food frequency questionnaire (FFQ) correlate with n-3 FA levels measured in plasma phospholipids (PL).
The study sample consisted of 200 French-Canadians men and women aged between 18 to 55?years. Dietary data were collected using a validated FFQ. Fasting blood samples were collected and the plasma PL FA profile was measured by gas chromatography.
Low intakes of n-3 long-chain FA together with low percentages of n-3 long-chain FA in plasma PL were found in French-Canadian population. Daily intakes of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) were similar between men and women. Yet, alpha-linolenic acid (ALA) and total n-3 FA intakes were significantly higher in men compared to women (ALA: 2.28?g and 1.69?g, p?
Bisphenol A (BPA) and phthalates are endocrine disruptors possibly linked to adverse reproductive and neurodevelopmental outcomes. These chemicals have commonly been measured in urine in population surveys; however, such data are limited for large populations of pregnant women, especially for the critical first trimester of pregnancy. The aim of the study was to measure BPA and phthalate metabolites in first trimester urine samples collected in a large national-scale pregnancy cohort study and to identify major predictors of exposure. Approximately 2000 women were recruited in the first trimester of pregnancy from ten sites across Canada. A questionnaire was administered to obtain demographic and socio-economic data on participants and a spot urine sample was collected and analyzed for total BPA (GC-MS/MS) and 11 phthalate metabolites (LC-MS/MS). The geometric mean (GM) maternal urinary concentration of total BPA, uncorrected for specific gravity, was 0.80 (95% CI 0.76-0.85) µg/L. Almost 88% of the women had detectable urinary concentrations of BPA. An analysis of urinary concentrations of BPA by maternal characteristics with specific gravity as a covariate in the linear model showed that the geometric mean concentrations: (1) decreased with increasing maternal age, (2) were higher in current smokers or women who quit during pregnancy compared to never smokers, and (3) tended to be higher in women who provided a fasting urine sample and who were born in Canada, and had lower incomes and education. Several of the phthalate metabolites analyzed were not prevalent in this population (MCHP, MMP, MiNP, MOP), with percentages detectable at less than 15%. The phthalate metabolites with the highest measured concentrations were MEP (GM: 32.02 µg/L) and MnBP (GM: 11.59 µg/L). MBzP urinary concentrations decreased with maternal age but did not differ by time of urine collection; whereas the DEHP metabolites tended to be higher in older women and when the urine was collected later in the day. This study provides the first biomonitoring results for the largest population of pregnant women sampled in the first trimester of pregnancy. The results indicate that exposure among this population of pregnant women to these chemicals is comparable to or even lower than that observed in a Canadian national population-based survey.