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.)

Current 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. Swedish 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. Of 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. Almost 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.

Objective: First, to describe the prevalence of both full and partial breast-feeding during the first 6 months; second, to study the associations between selected health service-related factors and cessation of full breast-feeding at three time intervals. Design: Retrospective questionnaires, 6 months after birth. Setting: The Norwegian Mother and Child Cohort Study (MoBa). Subjects: In total, 29 621 women. Results: While 96·6 %, 94·0 %, 90·8 %, 86·9 %, 83·8 % and 80·0 % of the infants were breast-fed at 1, 2, 3, 4, 5 and 6 months, respectively, the corresponding proportions for full breast-feeding were 84·6 %, 79·1 %, 70·9 %, 44·0 %, 16·7 % and 2·1 %. An increased risk of cessation of full breast-feeding during the first month was associated with supplementation during the first week of life with water (relative risk (RR) 1·77; 95 % CI 1·52, 2·06), sugar water (RR 1·73; 95 % CI 1·49, 2·00) or formula (RR 5·99; 95 % CI 5·58, 6·42). An increased risk was also associated with Caesarean delivery (RR 1·08; 95 % CI 1·00, 1·16) and breast-feeding problems (RR 1·56; 95 % CI 1·45, 1·67). Between months 1 and 3, the risk of cessation of full breast-feeding remained elevated in the case of supplementation during the first week of life with water (RR 1·29; 95 % CI 1·14, 1·45), sugar water (RR 1·48; 95 % CI 1·34, 1·64) or formula (RR 1·18; 95 % CI 1·07, 1·29). The same applied to Caesarean delivery (RR 1·15; 95 % CI 1·06, 1·25). Conclusions: Supplementation during the first week, breast-feeding problems and Caesarean delivery are associated with early cessation of full breast-feeding. The results support a cautious approach to supplementation during the first week of life.

Objectives To collect, appraise, select, and report the best available national estimates of cigarette consumption since 1970. Design Systematic collection of comparable data. Setting and population 71 of 214 countries for which searches for national cigarette consumption data were conducted, representing over 95% of global cigarette consumption and 85% of the world’s population. Main outcome measures Validated cigarette consumption data covering 1970-2015 were identified for 71 countries. Data quality appraisal was conducted by two research team members in duplicate, with greatest weight given to official government sources. All data were standardised into units of cigarettes consumed per year in each country, a detailed accounting of data quality and sourcing was prepared, and all collected data and metadata were made freely available in an open access dataset. Results Cigarette consumption fell in most countries over the past three decades but trends in country specific consumption were highly variable. For example, China consumed 2.5 million metric tonnes (MMT) of cigarettes in 2013, more than Russia (0.36 MMT), the United States (0.28 MMT), Indonesia (0.28 MMT), Japan (0.20 MMT), and the next 35 highest consuming countries combined. The US and Japan achieved reductions of more than 0.1 MMT from a decade earlier, whereas Russian consumption plateaued, and Chinese and Indonesian consumption increased by 0.75 MMT and 0.1 MMT, respectively. These data generally concord with modelled country level data from the Institute for Health Metrics and Evaluation and have the additional advantage of not smoothing year-over-year discontinuities that are necessary for robust quasi-experimental impact evaluations. Conclusions Before this study, publicly available data on cigarette consumption have been limited; they have been inappropriate for quasi-experimental impact evaluations (modelled data), held privately by companies (proprietary data), or widely dispersed across many national statistical agencies and research organisations (disaggregated data). This new dataset confirms that cigarette consumption has decreased in most countries over the past three decades, but that secular country specific consumption trends are highly variable. The findings underscore the need for more robust processes in data reporting, ideally built into international legal instruments or other mandated processes. To monitor the impact of the WHO Framework Convention on Tobacco Control and other tobacco control interventions, data on national tobacco production, trade, and sales should be routinely collected and openly reported.

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.