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 ...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 aswell 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.展开更多
Background: Psoriasis is a chronic T-cell-mediated immunological skin disease. The occurrence of the disease appears to differ with geography and ethnicity. There is a need for epidemiological data obtained from defin...Background: Psoriasis is a chronic T-cell-mediated immunological skin disease. The occurrence of the disease appears to differ with geography and ethnicity. There is a need for epidemiological data obtained from defined population-based studies, and the sex-specific differences observed in the natural history of the disease require more attention. Objectives: To describe the occurrence and risk of psoriasis in Norway by age and sex. Patients/methods: A population-based health survey was conducted in 1998 in Norwegian twins aged 19-31 years. The present study is based upon the self-reported history of psoriasis among the 8045 questionnaire responders. Results: Altogether, 334 (4.2%) reported a positive history of psoriasis. There were no sex differences in the overall prevalence rates, but significantly higher point-prevalences emerged in females in the teenage-year intervals. A fairly linear increase in incidence rates by every 4-year age-interval peaked at a lower age in females. The mean age at onset was also significantly lower in females (14.8 years) than in males (17.3 years). The absolute risk of developing psoriasis appeared higher for females across the entire age range. However, by the age of 31 the cumulative risks were similar in females and males (0.056 and 0.053, respectively). Conclusions: In this historical cohort of Norwegian twins, we find a high prevalence of psoriasis in congruence with previously reported data among whites in northwestern Europe. We have found sex-specific characteristics in point-prevalences and incidence rates which may contribute to the understanding of the earlier age at onset of the disease in females.展开更多
文摘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 aswell 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.
文摘Background: Psoriasis is a chronic T-cell-mediated immunological skin disease. The occurrence of the disease appears to differ with geography and ethnicity. There is a need for epidemiological data obtained from defined population-based studies, and the sex-specific differences observed in the natural history of the disease require more attention. Objectives: To describe the occurrence and risk of psoriasis in Norway by age and sex. Patients/methods: A population-based health survey was conducted in 1998 in Norwegian twins aged 19-31 years. The present study is based upon the self-reported history of psoriasis among the 8045 questionnaire responders. Results: Altogether, 334 (4.2%) reported a positive history of psoriasis. There were no sex differences in the overall prevalence rates, but significantly higher point-prevalences emerged in females in the teenage-year intervals. A fairly linear increase in incidence rates by every 4-year age-interval peaked at a lower age in females. The mean age at onset was also significantly lower in females (14.8 years) than in males (17.3 years). The absolute risk of developing psoriasis appeared higher for females across the entire age range. However, by the age of 31 the cumulative risks were similar in females and males (0.056 and 0.053, respectively). Conclusions: In this historical cohort of Norwegian twins, we find a high prevalence of psoriasis in congruence with previously reported data among whites in northwestern Europe. We have found sex-specific characteristics in point-prevalences and incidence rates which may contribute to the understanding of the earlier age at onset of the disease in females.
