Andrej Grjibovski

Genetic and environmental influences on symptomatic gallstone disease: A Swedish study of 43,141 twin pairs

The contribution of hereditary and environmental factors to the pathogenesis of symptomatic gallstone disease is still unclear. We estimated the relative importance of genetic and environmental factors by analyzing a large population of twins. For this purpose, the Swedish Twin Registry was linked with the Swedish inpatient‐discharge and causes of death registries for symptomatic gallstone disease and gallstone surgery–related diagnoses in 43,141 twin pairs born between 1900 and 1958. Concordance rates, correlations, and odds ratios were calculated for males, females, monozygotic, and dizygotic twins, respectively, as well as for twin pairs of opposite sex. Structural equation modeling techniques were used to estimate the contributions of genetic effects as well as shared and non‐shared environmental factors to the development of symptomatic gallstone disease. We found that concordances and correlations were higher in monozygotic compared with dizygotic twins, both for males and females. Of note, there were no significant sex differences in heritability. In the full model, genetic effects accounted for 25% (95% CI, 9%–40%), shared environmental effects for 13% (95% CI, 1%–25%), and unique environmental effects for 62% (95% CI, 56%–68%) of the phenotypic variance among twins. In conclusion, our results show heritability to be a major susceptibility factor for symptomatic gallstone disease, consistent with results from previous, much smaller studies. (HEPATOLOGY 2005.)

Adherence to physical activity recommendations and the influence of socio-demographic correlates - a population-based cross-sectional study.

BackgroundCurrent physical activity guidelines acknowledge the importance of total health enhancing physical activity (HEPA) compared to leisure time physical activity or exercise alone. Assessing total HEPA may result in different levels of adherence to these as well as the strength and/or direction of associations observed between total HEPA and socio-demographic correlates. The aim of this study was to estimate the proportion of the population adhering to the recommendation of at least 30 minutes of HEPA on most days, and to examine the influences of socio-demographic correlates on reaching this recommendation.MethodsSwedish adults aged 18–74 years (n = 1470) were categorized, based on population data obtained using the IPAQ, into low, moderately and highly physically active categories. Independent associations between the physical activity categories and socio-demographic correlates were studied using a multinomial logistic regression.ResultsOf the subjects, 63% (95% CI: 60.5–65.4) adhered to the HEPA recommendation. Most likely to reach the highly physical active category were those aged < 35 years (OR = 1.8; 95% CI: 1.1–3.3), living in small towns (OR = 1.8; 95% CI: 1.1–2.7) and villages (OR = 2.4; 95% CI: 1.6–3.7), having a BMI between 25.0–29.9 kg/m2 (OR = 2.7; 95% CI: 1.4–5.3) having a BMI < 25 kg/m2 (OR = 2.5; 95% CI: 1.3–4.9), or having very good (OR = 2.1; 95% CI: 1.3–3.3) or excellent self-perceived health (OR = 4.1; 95% CI: 2.4–6.8). Less likely to reach the high category were women (OR = 0.6; 95% CI: 0.5–0.9) and those with a university degree (OR = 0.5; 95% CI: 0.3–0.9). Similar, but less pronounced associations were observed for the moderate group. Gender-specific patterns were also observed.ConclusionAlmost two-thirds of the Swedish adult population adhered to the physical activity recommendation. Due to a large diversity in levels of physical activity among population subgroups, social-ecological approaches to physical activity promotion may be warranted.

Variations in prevalence of hyperemesis gravidarum by country of birth: a study of 900,074 pregnancies in Norway, 1967-2005.

Objective: To estimate the prevalence of hyperemesis gravidarum (HG) in women living in Norway by their country of birth, and explore whether the variations in the occurrence of HG could be explained by the differences in maternal sociodemographic factors. Design: This was a cross-sectional study. Methods: All primiparous women registered in the Medical Birth Registry of Norway (MBRN) from 1967 through June 2005 (N=900,074) comprised the sample. Data on HG, age, plurality and sex of the fetus were obtained from the MBRN and linked to the data on country of birth and maternal education obtained from Statistics Norway. Independent associations between country of birth and HG were studied by multiple logistic regression with and without adjustment for potential confounders. Results: The overall prevalence of HG in primiparous women in Norway during the study period was 0.89% (95% confidence interval (CI) 0.88—0.92). Women born in Western Europe had the lowest prevalence of HG (0.8%), whereas those born in India and Sri Lanka had the highest (3.2%). Women born in Africa (except North Africa) and India or Sri Lanka were 3.4 (95% CI 2.7— 3.5) and 3.3 (95% CI 2.6—3.4) times more likely to develop HG than women born in Norway, after adjustment for potential confounders. Conclusions: Substantial variations in the prevalence of HG in Norway by country of birth cannot be explained by the differences in maternal sociodemographic factors.

Prevalence of the metabolic syndrome and its components in Northwest Russia: the Arkhangelsk study.

BackgroundThe metabolic syndrome (MetS) is a cluster of risk factors associated with morbidity from cardiovascular disease (CVD) and associated mortality. Russia has one of the highest CVD mortality rates in the world. However, the prevalence of MetS in Russia remains largely unknown. The aim of this study is to estimate the prevalence of MetS and its components in an urban Russian setting.MethodsAltogether, 3705 Russian adults aged 18-90 years were enrolled in a cross-sectional study in Arkhangelsk (Northwest Russia). All subjects completed a questionnaire and underwent a physical examination. Blood samples were taken and analyzed in TromsØ, Norway. Three separate modified definitions of MetS were used, namely, the National Education Cholesterol Education Program Adult Treatment Panel III (NCEP), the American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) and the International Diabetes Federation (IDF). To ensure comparability of the findings, the prevalence data were standardized using world and European standard populations and Russian population.ResultsThe age-standardized (Segis world standard population) prevalence rates of the MetS among women were 19.8% (95% CI: 18.1-21.5), 20.6% (95% CI: 18.9-22.3) and 23.1% (95% CI: 21.3-24.9) by the NCEP, AHA/NHLBI and IDF criteria, respectively. The corresponding rates for men were 11.5% (95% CI: 10.1-12.9), 13.7% (95% CI: 12.2-15.2) and 11.0% (95% CI: 9.7-12.4). Among subjects with MetS, central obesity was more common among women, while elevated triglycerides and blood glucose were more common among men. Almost perfect agreement was found between the NCEP and AHA/NHLBI criteria (κ = 0.94). There was less agreement between the used definitions of MetS in men than in women.ConclusionsWhile the prevalence of MetS among Russian women is comparable to the data for Europe and the U.S., the prevalence among Russian men is considerably lower than among their European and North-American counterparts. Our results suggest that MetS is unlikely to be a major contributor to the high cardiovascular mortality among Russian men. Further studies of MetS determinants and associated cardiovascular risk are needed for a better understanding of the mechanisms leading to the exceptionally high cardiovascular mortality in Russia.

The association between health enhancing physical activity and neighbourhood environment among Swedish adults - a population-based cross-sectional study.

BackgroundThis study examines the relationship of neighbourhood environment factors with walking and total health enhancing physical activity.MethodsA population-based cross-sectional study. The short self-administered version of the validated International Physical Activity Questionnaire (IPAQ) was used to assess health enhancing physical activity including walking. The neighbourhood environment was assessed using a 17-item environmental module. A principal component analysis among the environmental variables was conducted. The factor scores were divided into tertiles and independent associations between factor tertiles and physical activity categories and walking were studied by multinomial logistic regression with adjustment for confounders.ResultsIn adjusted models, a lower odds ratio (OR) for reaching the middle, OR: 0.66 (95% Confidence Interval (CI): 0.47–0.98), and upper, OR: 0.65 (0.45–0.95), tertile of walking was observed among those in the lowest tertile of the degree of urbanisation. A higher OR for reaching the middle, OR: 1.84 (1.28–1.64), and upper tertile, OR: 1.64 (1.14–2.36), of walking was observed among those in the lowest tertile of fear of crime. A higher OR for reaching the high category of total health enhancing physical activity was observed among those in the lowest, OR: 2.01 (1.32–3.05), and middle tertile, OR: 1.52 (1.02–2.25), of the factor degree of urbanisation.ConclusionThe findings suggest that the environment is differentially related to walking and total health enhancing physical activity. This should be explored in future research to disentangle the complex relationship between different levels and aspects of physical activity and their relationship with the environment.

Housing conditions, perceived stress, smoking, and alcohol: determinants of fetal growth in Northwest Russia

Background.  Social determinants of health have become important in countries of the former Soviet Union during the time of transition.

Socio-demographic determinants of initiation and duration of breastfeeding in northwest Russia.

Aim: This study examines socio‐demographic determinants of initiation and duration of breastfeeding in a community‐based cohort in northwest Russia. Methods: All infants born to women who were registered at the antenatal clinics in Severodvinsk in 1999 comprised the cohort (n=1399) and were followed up at 1 y. Data on maternal and infant characteristics as well as the duration of breastfeeding were obtained from medical records. Proportional hazard analysis was applied to quantify the effect of the selected factors on the risk of breastfeeding discontinuation adjusted for potential confounders. Results: Only 1.3% of infants were never breastfed. Breastfeeding rates were 75.0% and 47.2% at 3 and 6 mo, respectively. Maternal age and early initiation of prenatal care were positively associated with breastfeeding initiation rates. Increased risks of breastfeeding discontinuation were found in teenage mothers (OR=1.45, 95% CI: 1.06–1.99), in mothers with basic education (OR=1.68, 95% CI: 1.06–2.66) and in unmarried mothers (OR=1.19, 95% CI: 1.03–1.38). Women with no previous deliveries were more likely to breastfeed longer (OR=0.74, 95% CI: 0.62–0.90).

Dietary intake among under-, normal- and overweight 9- and 15-year-old Estonian and Swedish schoolchildren

OBJECTIVES To determine the differences in macronutrient and food group contribution to total food and energy intakes between Estonian and Swedish under-, normal- and overweight schoolchildren, and to estimate the association between diet and body mass index (BMI). DESIGN Cross-sectional comparison between Estonian and Swedish children and adolescents of different BMI groups. SETTING Twenty-five schools from one region in Estonia and 42 in two regions of central Sweden. SUBJECTS In total 2308 participants (1176 from Estonia and 1132 from Sweden), including 1141 children with a mean age of 9.6 +/- 0.5 years and 1167 adolescents with a mean age of 15.5 +/- 0.6 years. RESULTS Overweight was more prevalent among younger girls in Sweden (17.0 vs. 8.9%) and underweight among girls of both age groups in Estonia (7.9 vs. 3.5% in younger and 10.5 vs. 5.1% in older age group of girls). Compared with that of normal- and underweight peers, the diet of overweight Estonian children contained more energy as fat (36.8 vs. 31.7%) but less as carbohydrates, and they consumed more milk and meat products. Absolute BMI of Estonian participants was associated positively with energy consumption from eggs and negatively with energy consumption from sweets and sugar. Swedish overweight adolescents tended to consume more energy from protein and milk products. Risk of being overweight was positively associated with total energy intake and energy from fish or meat products. In both countries the association of overweight and biological factors (pubertal maturation, parental BMI) was stronger than with diet. CONCLUSION The finding that differences in dietary intake between under-, normal- and overweight schoolchildren are country-specific suggests that local dietary habits should be considered in intervention projects addressing overweight.

Decrease in consanguinity among parents of children born in Norway to women of Pakistani origin: a registry-based study.

Aims: To describe the prevalence of consanguinity among Norwegian Pakistani parents in the period from 1995 to 2005. Methods: All first births to women of Pakistani origin in 1995—2005 (n = 1962) were identified by linking the Medical Birth Registry of Norway with information on country of origin and country of birth from Statistics Norway. Prevalence ratios (PRs) and prevalence differences were calculated by multiple binomial regression analyses with adjustment for maternal age and education. Women born in Pakistan who gave birth in Norway in 1995—97 formed the reference group. Results: The proportion of women who were consanguineously related to their co-parent decreased from 45.5% in 1995—97 to 27.3% in 2002—2005 among those who were born in Pakistan, and from 48.3% to 18.8% among women of Pakistani origin who were born in Norway. The proportion of women who were related to their co-parent as first cousin decreased from 37.7% to 24.7% among women born in Pakistan, and from 43.3% to 16.7% among women of Pakistani origin who were born in Norway. The proportion of births to women with an unrelated co-parent increased by 25% for women born in Pakistan (PR = 1.25, 95% confidence interval (CI) = 1.12—1.39), and by 53% for women of Pakistani origin born in Norway (PR = 1.53, 95% CI = 1.35—1.74). Conclusions: In contrast to previous reports from the UK, our analysis suggests that there is a decrease in the proportion of consanguineously related parents of children born to women of Pakistani origin in Norway.

A dropout analysis of the second phase of the Swedish part of the European Youth Heart Study

The European Youth Heart Study (EYHS) addresses cardiovascular disease risk factors and their determinants in European children and adolescents. The Swedish part of the study began with cross-sectional data collection in 9- and 15-year-old schoolchildren in 1998–1999 (EYHS-I). Repeated observations of the key indicators were performed in 2004–2005 (EYHS-II). The purpose of this study was to assess potential dropout effects in EYHS-II. Participants in both EYHS-I and EYHS-II (n=459) were compared with dropouts who participated only in the EYHS-I (n=678) in relation to baseline physical activity, cardiorespiratory fitness and socioeconomic and anthropometric characteristics. Bivariate comparisons were performed using chi-square tests and gamma tests for nominal and ordinal data, respectively. Continuous data were compared by t tests and Mann−Whitney tests depending on the distribution. The Bonferroni correction was used to control for multiple hypothesis testing. Multiple logistic regression with backward elimination of variables was applied to study independent effects of variables on the probability of becoming a dropout. Analyses were performed separately for the younger and older age groups. The dropout proportion in EYHS-II was 60%. Subjects from the older age group were less likely to participate in the follow-up study (32% vs. 50%, p<0.001). In bivariate analyses, only maternal education was associated with dropout rates in the younger age group after Bonferroni correction. Males were more likely to drop out in both younger [odds ratio (OR)=1.72; 95% confidence interval (CI): 1.10, 2.96] and older (OR=1.96; 95% CI: 1.09, 3.54) age groups while basic maternal education was associated with outcome only in the younger group (OR=4.31; 95% CI: 1.78, 2.95) in regression analysis. The Swedish EYHS-II had high dropout rate after EYHS-I, but the dropouts did not differ from the participants in relation to physical activity, physical fitness, and anthropometric indices. Males were more likely to drop out than were females in both age groups. Differential dropout in relation to maternal education was observed in the younger age group.