Prevalence of prediabetes and type 2 diabetes in two non-random populations aged 44-77 years in the Faroe Islands

AIMS

The prevalence of type 2 diabetes is increasing worldwide but little known about the status in the Faroe Islands. The aim was therefore to determine the prevalence of type 2 diabetes mellitus and prediabetes in two non-random populations aged 44-77 years.

METHODS

This cross-sectional survey was conducted between 2011 and 2012 and included two sub-populations, namely 518 Septuagenarians aged 74-77 years (84% of the invited) and 401 Mark aged 44-73 years (87% of the invited). Subjects were screened for glycosylated haemoglobin, type A1c, non-fasting random plasma glucose, fasting plasma glucose followed by an oral glucose tolerance test. The screening was based on a diagnostic algorithm that included screening, diagnostic and confirmatory steps.

RESULTS

Each group was analysed separately. In the Septuagenarian group 20.4% had type 2 diabetes, with 5.2% being newly detected and a total of 59% had prediabetes. In the Mark group 4.1% had diabetes, with 2.1% being newly detected and 22.3% had prediabetes. Diabetes increased with age and was significantly more prevalent among men. Women had lower mean fasting plasma glucose concentrations and men had lower values for 2-hours plasma glucose. Significant predictors associated with diabetes mellitus included obesity (BMI ≥ 30, abnormal waist/hip ratio and vegetable consumption.

CONCLUSIONS

Among the Faroese populations studied, the prevalence of type 2 diabetes increased with age and was more prevalent among men. The detected prevalence was comparable to other Nordic countries for all age-groups.

Prevalence of type 2 diabetes and prediabetes in the Faroe Islands

AIMS

To determine the prevalence of type 2 diabetes mellitus and prediabetes among the population aged 40-74 years in the Faroe Islands.

METHODS

This population-based cross-sectional survey, conducted between 2011 and 2012, invited 2186 randomly selected individuals (corresponding to 11.1% of the entire population aged 40-74 years). Subjects were screened using finger capillary blood for glycosylated hemoglobin, type A1c, non-fasting random plasma glucose, fasting plasma glucose followed by oral glucose tolerance test. The test was based on an algorithm that accounts for screening, diagnostic and confirmatory steps. Anthropometric measures and a questionnaire including medical history, medication, hereditary conditions, and food intake were included.

RESULTS

The study included 1772 participants. Of the 1772, 169 (9.5%) had type 2 diabetes mellitus (3.0% of which were diagnosed upon study inclusion), thus 31.4% of subjects with diabetes were undiagnosed at the time of examination. A total of 271 (15.3%) had prediabetes. Diabetes was more prevalent among men, significantly from age ≥60 years. Women had lower mean fasting plasma glucose concentrations and men had lower values for 2-h plasma glucose. Predictors associated with diabetes mellitus included obesity (BMI ≥ 30), abnormal waist/hip ratio, history of hypertension or cardiovascular attack and family history of diabetes mellitus and leisure activity.

CONCLUSIONS

The prevalences of diabetes and prediabetes increased with age and were more frequent among men. The detected prevalence in the Faroe Islands was slightly higher than other Nordic countries.

Overview of ongoing cohort and dietary studies in the Arctic

This article gives an overview of the ongoing cohort and dietary studies underlying the assessment of population health in the Arctic. The emphasis here is on a description of the material, methods and results or preliminary results for each study. Detailed exposure information is available in an article in this journal, whereas another paper describes the effects associated with contaminant exposure in the Arctic. The cohort descriptions have been arranged geographically, beginning in Norway and moving east to Finland, Sweden, Russia and the other Arctic countries and ultimately to the Faroe Islands. No cohort studies have been reported for Alaska or Iceland.

Health effects associated with measured levels of contaminants in the Arctic

The Human Health Assessment Group has over the past decade recommended that effect studies be conducted in the circumpolar area. Such studies examine the association between contaminant exposure in the Arctic populations and health effects. Because foetuses and young children are the most vulnerable, effect studies are often prospective child cohort studies. The emphasis in this article is on a description of the effects associated with contaminant exposure in the Arctic. The main topics addressed are neurobehavioural, immunological, reproductive, cardiovascular, endocrine and carcinogenic effect. For each topic, the association between exposure and effects is described, and some results are reported for similar studies outside the Arctic.

Sperm Aneuploidy in Faroese Men with Lifetime Exposure to Dichlorodiphenyldichloroethylene (p,p´-DDE) and Polychlorinated Biphenyl (PCB) Pollutants

BACKGROUND

Although it is known that sperm aneuploidy contributes to early pregnancy losses and congenital abnormalities, the causes are unknown and environmental contaminants are suspected.

OBJECTIVES

Our goal was to evaluate associations between lifetime exposure to organochlorines, specifically dichlorodiphenyldicholorethylene (p,p´-DDE) and polychlorinated biphenyls (PCBs), and sperm aneuploidy in men from the general population of the Faroe Islands, a population with a known history of organochlorine exposures.

METHODS

Serum and semen samples from men (n = 90) 22-44 years old who participated in Faroe Islands health studies were analyzed for p,p´-DDE and PCBs 118, 138, 153, and 180 and adjusted for total lipids. Cord blood and age-14 serum were available for a subgroup (n = 40) and were also analyzed for p,p´-DDE and PCBs. Sperm fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 was used to determine rates of XX18, XY18, YY18, and total disomy. Multivariable adjusted Poisson models were used to estimate the relationship between organochlorine exposure and sperm disomy outcomes.

RESULTS

Adult p,p´-DDE and total PCB serum concentrations were both associated with significantly increased rates of XX18, XY18, and total disomy. Age-14 p,p´-DDE and PCB concentrations were both associated with significantly increased rates of XX, XY, and total disomy in adulthood. Associations between cord blood concentrations of p,p´-DDE and PCBs and sperm disomy in adulthood were not consistently significant.

CONCLUSIONS

Organochlorine exposures measured at age 14 and in adulthood were associated with sperm disomy in this sample of high-exposure men, suggesting that the impacts of persistent pollutants on testicular maturation and function require further investigation.

CITATION

Perry MJ, Young HA, Grandjean P, Halling J, Petersen MS, Martenies SE, Karimi P, Weihe P. 2016. Sperm aneuploidy in Faroese men with lifetime exposure to dichlorodiphenyldichloroethylene (p,p´-DDE) and polychlorinated biphenyl (PCB) pollutants. Environ Health Perspect 124:951-956; http://dx.doi.org/10.1289/ehp.1509779.

Vitamin d in the general population of young adults with autism in the faroe islands

Vitamin D deficiency has been proposed as a possible risk factor for developing autism spectrum disorder (ASD). 25-Hydroxyvitamin D₃ (25(OH)D₃) levels were examined in a cross-sectional population-based study in the Faroe Islands. The case group consisting of a total population cohort of 40 individuals with ASD (aged 15–24 years) had significantly lower 25(OH)D₃ than their 62 typically-developing siblings and their 77 parents, and also significantly lower than 40 healthy age and gender matched comparisons. There was a trend for males having lower 25(OH)D₃ than females. Effects of age, month/season of birth, IQ, various subcategories of ASD and Autism Diagnostic Observation Schedule score were also investigated, however, no association was found. The very low 25(OH)D₃ in the ASD group suggests some underlying pathogenic mechanism.

Spermatogenic capacity in fertile men with elevated exposure to polychlorinated biphenyls

BACKGROUND

Endocrine disrupting industrial chemicals, such as polychlorinated biphenyls (PCBs), are suspected to adversely affect male reproductive functions.

OBJECTIVES

The Faroe Islands community exhibits an unusually wide range of exposures to dietary contaminants, and in this setting we examined the possible association between PCB exposure and semen quality and reproductive hormones in fertile Faroese men.

METHODS

Participants in this cross-sectional study include 266 proven fertile men residing in the Faroe Islands. PCB levels and hormone profiles were measured in serum samples taken at the clinical examination that included semen quality parameters.

RESULTS

A significant positive association was seen between serum-PCB and the testosterone/estradiol ratio (p=0.04). In the unadjusted analyses, elevated PCB exposure was associated with increased serum concentrations of SHBG (p=0.01) and FSH (p=0.05). We found no association between the serum PCB concentration and the semen quality variables.

CONCLUSION

In this population of highly exposed fertile men, the current serum-PCB concentration was associated with higher androgen/estrogen ratio. Further studies are needed to establish the findings and further document PCB-associated hormonal effects, any time windows of increased susceptibility, and the role of PCB in sub-fecundity.

Exposure to persistent organic pollutants and sperm sex chromosome ratio in men from the Faroe Islands

People in the Arctic as well as fishermen on the polluted Swedish east coast are highly exposed to persistent organic pollutants (POPs). These compounds have been shown to affect the sperm Y:X chromosome ratio. In present study, the aim was to investigate whether polychlorinated biphenyl (PCB) congeners and 1,1,-dichloro-2,2,-bis(p-chlorophenyl)ethane (p,p'-DDE) influence sperm sex chromosome ratio in Faroese men, and whether these men differ regarding Y:X ratio compared to Greenland Inuit and Swedish fishermen. The study population (n=449) consisted of young men from the general population (n=276) as well as proven fertile men (n=173). The Y:X ratio was assessed by fluorescent in situ hybridization. Serum concentrations of POPs were measured using gas chromatography. Associations between POP concentrations and Y:X ratio were calculated using linear and non-linear regression models as well as trend analysis and pairwise comparison of exposure data categorized into quartiles. The selected POPs were associated with Y:X ratio in fertile Faroese men, but not in the total population; p,p'-DDE (95% CI for B=-0.005 to -0.001, p=0.005) and ΣPCB (95% CI for B=-0.005 to -0.001, p=0.012). Since p,p'-DDE and ΣPCB correlated significantly (r=0.927, p<0.001), the results involving the exposure variables can be regarded as a single finding. The Y:X ratio for the total Faroese population was 0.500±0.018, which was statistically significantly lower than in both Inuit and Swedish fishermen (0.512 for both). In conclusion, Faroese men presented with lower Y:X ratio than Greenland Inuit and Swedish fishermen. Although no direct health effects are expected due to the lower Faroese Y:X ratio, it could be indicative of adverse effects on the reproductive system.

Semen quality and reproductive hormones in Faroese men: a cross-sectional population-based study of 481 men

OBJECTIVES

To determine semen quality and reproductive hormone levels in young Faroese men.

DESIGN

Descriptive cross-sectional study of Faroese men compared with Danish men.

SETTING

Faroese one-centre study.

PARTICIPANTS

481 men born from 1981 to 1987 and investigated from 2007 to 2010.

OUTCOME MEASURES

Sperm concentration, semen volume, total sperm count, sperm motility, sperm morphology and reproductive hormone levels.

RESULTS

Sperm concentrations for the Faroese men were lower than for the Danish men (crude median 40 vs 48 mill/ml, p<0.0005). Semen volume was higher, and thus the total sperm counts did not differ (159 vs 151 mill, p=0.2). Motility and morphology did not differ between the Faroese and Danes. The inhibin B/follicle-stimulating hormone ratios for the Faroese men were lower than for the Danes (64 vs 76, p=0.001). Similarly, lower total testosterone/luteinising hormone (LH) ratio (4.6 vs 6.0, p<0.0005) and lower calculated free-testosterone/LH ratio (94 vs 134, p<0.0005) were detected for the Faroese men.

CONCLUSIONS

Semen quality among the Faroese men is at the same low level as reported for Danish men, and the reproductive hormone levels furthermore indicated a lower Leydig cell capacity for testosterone production. The influence of environmental exposure and genetic factors on semen quality has to be studied further.

Linkage disequilibrium between the CYP2C19*17 allele and wildtype CYP2C8 and CYP2C9 alleles: identification of CYP2C haplotypes in healthy Nordic populations

PURPOSE

To determine the distribution of clinically important CYP2C genotypes and allele frequencies in healthy Nordic populations with special focus on linkage disequilibrium.

METHODS

A total of 896 healthy subjects from three Nordic populations (Danish, Faroese, and Norwegian) were genotyped for five frequent and clinically important CYP2C allelic variants: the defective CYP2C8*3, CYP2C9*2, CYP2C9*3, and CYP2C19*2 alleles, and the CYP2C19*17 allele that causes rapid drug metabolism. Linkage disequilibrium was evaluated and CYP2C haplotypes were inferred in the entire population.

RESULTS

Ten CYP2C haplotypes were inferred, the most frequent of which (49%) was the CYP2C wildtype haplotype carrying CYP2C8*1, CYP2C9*1, and CYP2C19*1. The second most frequent haplotype (19%) is composed of CYP2C19*17, CYP2C8*1, and CYP2C9*1. This predicted haplotype accounts for 99.7% of the CYP2C19*17 alleles found in the 896 subjects.

CONCLUSION

CYP2C19*17 is a frequent genetic variant in Nordic populations that exists in strong linkage disequilibrium with wildtype CYP2C8*1 and CYP2C9*1 alleles, which effectively makes it a determinant for a haplotype exhibiting an efficient CYP2C substrate metabolism.

Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults

The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6beta-hydroxycortisol/cortisol (6beta-OHC/FC) ratio. POP exposures were assessed by measuring their concentrations in serum lipid. The results showed a unimodal distribution of the 6beta-OHC/FC ratio with values ranging from 0.58 to 27.38. Women had a slightly higher 6beta-OHC/FC ratio than men (p=0.07). Confounder-adjusted multiple regression analysis showed significant associations between 6beta-OHC/FC ratios and summation PCB, PCB-TEQ and p,p'-DDE, o,p'-DDT and HCB, respectively, but the associations were statistically significant for men only.

The CYP2D6 polymorphism in relation to the metabolism of amitriptyline and nortriptyline in the Faroese population

AIM

To determine the frequency of CYP2D6 poor metabolizers (PMs) in a Faroese patient group medicated with amitriptyline (AT) and to investigate plasma concentrations of AT and metabolites in relation to CYP2D6.

METHODS

CYP2D6 phenotype and genotype were determined in 23 Faroese patients treated with AT. Plasma concentrations of AT and metabolites were determined by high-performance liquid chromatography and investigated in relation to CYP2D6 activity.

RESULTS

Of the 23 patients phenotyped and genotyped, five (22%) (95% confidence interval 7.5, 43.7) were CYP2D6 PMs. No difference was found in AT daily dosage between PMs (median 25 mg day(-1); range 5-80) and extensive metabolizers (EMs) (median 27.5 mg day(-1); range 10-100). The (E)-10-OH-nortriptyline (NT)/dose concentrations were higher in EMs than in PMs and the NT/(E)-10-OH-NT and AT/(E)-10-OH-AT ratios were higher in PMs compared with EMs. The log sparteine metabolic ratio correlated positively with the NT/(E)-10-OH-NT ratio (r(s) = 0.821; P < 0.0005) and the AT/(E)-10-OH-AT ratio (r(s) = 0.605; P < 0.006).

CONCLUSION

A high proportion of CYP2D6 PMs was found in a Faroese patient group medicated with AT. However, similar doses of AT and concentrations of AT and NT were noted in EMs and PMs, probably due to varying doses and indications for AT treatment.

Caffeine N3-demethylation (CYP1A2) in a population with an increased exposure to polychlorinated biphenyls

OBJECTIVE

To investigate the CYP1A2 phenotype distribution in a population with an increased exposure to polychlorinated biphenyls (PCBs) that would likely induce an increased activity of this enzyme. Further, to investigate the effect of sex, smoking, and oral contraceptive use on the CYP1A2 activity.

METHODS

In 305 randomly selected Faroese residents aged 18-60 years, the CYP1A2 activity was determined following oral intake of a caffeine dose and subsequent determination of the urinary metabolites and calculation of the caffeine metabolic ratio (CMR). PCB exposure was assessed by measuring the serum concentration of major congeners.

RESULTS

The CYP1A2 phenotype distribution was unimodal. The CMR was significantly higher both in smoking men and in smoking women, independent of oral contraceptive use, as compared with non-smokers. Among non-smokers, the CMR was significantly higher in women not using oral contraceptives than in those using oral contraceptives; a similar difference could not be established among smokers. The CMR appeared higher in men than in women, but stratified analyses confirmed a significant sex-related difference only among smokers not using oral contraceptives. Overall, the mean CMR in Faroese was significantly higher compared with the mean CMR in Danish historical controls. No association was found with PCB exposure and individual PCB congeners, except for one of three dioxin-like congeners, in confounder-adjusted multiple regression analyses.

CONCLUSION

The CYP1A2 phenotype in Faroese residents was unimodally distributed and showed the inducing effect of smoking and the inhibiting effect of use of oral contraceptives, but a sex-related difference was not apparent after confounder adjustment. There was no statistically significant association between CMR and PCB exposure.

Microslip between a Rolling Element and its Track Arising from Geometric Conformity and Applied Surface Tractions

The shape of the microslip areas between a rolling element and its track are obtained by an approximate analysis which utilizes a two-dimensional strain solution applied to elemental strips in the contact zone. The effects of surface tractions and geometric conformity between the rolling element and its track are considered. From this solution it is possible to derive the overall creep arising from such microslip. In particular the condition of zero overall creep is considered as being a useful design criteria for minimum wear in rolling situations. The particular case of wheels rolling along rails is developed as a special solution in which the geometric shapes for both wheel and rail are considered in relation to the applied tractions.

An Analysis of the Plastic Interaction of Surface Asperities and its Relevance to the Value of the Coefficient of Friction

Surface asperities are considered as wedge-shaped bodies which are plastically deformed wherever relative motion occurs between mating surfaces. This plastic interaction produces interfacial forces between the surface asperities which are considered, in the collective sense, to represent the total applied normal and tangential forces acting on the sliding surfaces. A solution is proposed which enables the values of the interfacial forces to be obtained at each time interval during the life history of a junction interaction. Furthermore, it is shown that the nature of these forces is markedly dependent on both the initial asperity geometry and on the nature of any surface films which may be present at the asperity interfaces. From such results it is possible to predict the macroscopic values of the coefficient of sliding friction. Such results suggest that an earlier solution due to Tabor should be considered as the special case for perfectly plane surfaces. The solution also indicates the nature of the plastic deformation of the asperities and displays the phenomena of junction growth. Furthermore, it is demonstrated that very large values of the macro-scopic coefficient of friction are associated with very strong molecular adhesion of the surface asperities particularly for materials having high ductility.

Experimental Study of the Plastic Interaction of Model Surface Asperities during Sliding

The paper describes an experimental study of the plastic interaction of triangular shaped lead model asperities deformed under conditions of plane strain. The investigation yields values of the normal and tangential force variations throughout the junction interaction and details of the plastic deformation particularly in relation to junction growth. A number of asperity interfacial conditions are considered ranging from complete adhesion to very low shear strengths achieved using p.t.f.e. strip. The experimental results are compared with an earlier theoretical solution to this problem and show reasonable agreement with the theoretical predictions. In particular it is shown that the normal force, which is usually compressive, may become tensile for conditions of high adhesion between the asperities. This leads to very high values of the macroscopic friction coefficient such as occur in hard vacuum situations. The experimental results for the various surface conditions show sufficient agreement with theoretical predictions to justify the use of this type of theoretical approach for the wider study of the friction and wear of mating surfaces.

Polymorphism of CYP2D6, CYP2C19, CYP2C9 and CYP2C8 in the Faroese population

OBJECTIVE

The purpose of the study was to study the distribution of poor and extensive metabolizers of CYP2C19 and CYP2D6 and to genotype for CYP2C8 and CYP2C9 among 312 randomly selected Faroese.

METHODS AND RESULTS

The participants were phenotyped for CYP2D6 with the use of sparteine. The distribution of the sparteine metabolic ratio (sparteine/didehydrosparteines) was bimodal, and 14.5% (n=44; 95% CI: 10.7--18.9%) of the subjects were phenotyped as poor metabolizers. The frequency of poor metabolizers was higher (P=0.0002; chi(2) test) among the Faroese than in other European populations (7.4%). Genotype analyses for the CYP2D6*3, *4, *6 and *9 alleles were performed using real-time polymerase chain reaction (PCR) (TaqMan, Foster City, CA, USA), and we found 14.6% (n=45) (95% CI: 10.8--19.0%) with deficient CYP2D6 genes (*3/*4, *4/*4, *4/*6, *6/*6) in the Faroese population. The subjects were phenotyped for CYP2C19 with the use of mephenytoin and 10 subjects, i.e., 3.2% (95% CI: 1.6--5.9%) were phenotyped as poor metabolizers. Genotype analysis for the CYP2C19*2 and *3 alleles was performed by means of PCR analysis, and 2.9% (n=9) (95% CI: 1.3-5.4%) of the Faroese were found to have a deficient CYP2C19 gene all explained by the CYP2C19*2/*2 genotype. The allele frequencies of the CYP2C9*2 and CYP2C9*3 alleles were 8.8% (95% CI: 6.7--11.4%) and 5.3% (95% CI: 3.7--7.4%), respectively, while the CYP2C8*3 allele frequency was 6.9% (95% CI: 5.0--9.2%). Real-time PCR (TaqMan) was used for both CYP2C9 and CYP2C8 genotype analyses.

CONCLUSION

The frequency of CYP2D6 poor metabolizers is twofold higher among the Faroese population than other Caucasians, while the frequencies of Faroese subjects with decreased CYP2C19, CYP2C8 and CYP2C9 enzyme activity are the same as seen in other Caucasian populations. A possible consequence might be a higher incidence of side effects among Faroese patients taking pharmaceuticals that are CYP2D6 substrates.

Dietitians view the horizon

In honor of the American Dietetic Association's landmark 75th anniversary, FM asked ADA members representing six market sectors to share their perspectives on the opportunities & challenges for dietitians in the '90s. An exciting era lies ahead.

Toward a Mechanical Wear Equation

It is first shown that the simple form of linear wear/load relation of the adhesive and abrasive wear laws arises from the nature of the asperity distribution. Without recourse to specific wear mechanisms, simple concepts for material properties, size of wear particles, and the production of wear particles are introduced. This procedure leads to an increasing appreciation of those factors which might be embraced by the specific wear constant. Of particular interest is the role of ductility in wear behavior. Finally, these ideas are extended to deal with the wear of surface films where it is seen that the film thickness is of paramount importance. Some experimental evidence for the concepts used is also provided.