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- Brooke, Hannah L, et al.
(författare)
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Methodological choices affect cancer incidence rates : a cohort study.
- 2017
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Ingår i: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Incidence rates are fundamental to epidemiology, but their magnitude and interpretation depend on methodological choices. We aimed to examine the extent to which the definition of the study population affects cancer incidence rates.METHODS: All primary cancer diagnoses in Sweden between 1958 and 2010 were identified from the national Cancer Register. Age-standardized and age-specific incidence rates of 29 cancer subtypes between 2000 and 2010 were calculated using four definitions of the study population: persons resident in Sweden 1) based on general population statistics; 2) with no previous subtype-specific cancer diagnosis; 3) with no previous cancer diagnosis except non-melanoma skin cancer; and 4) with no previous cancer diagnosis of any type. We calculated absolute and relative differences between methods.RESULTS: Age-standardized incidence rates calculated using general population statistics ranged from 6% lower (prostate cancer, incidence rate difference: -13.5/100,000 person-years) to 8% higher (breast cancer in women, incidence rate difference: 10.5/100,000 person-years) than incidence rates based on individuals with no previous subtype-specific cancer diagnosis. Age-standardized incidence rates in persons with no previous cancer of any type were up to 10% lower (bladder cancer in women) than rates in those with no previous subtype-specific cancer diagnosis; however, absolute differences were <5/100,000 person-years for all cancer subtypes.CONCLUSIONS: For some cancer subtypes incidence rates vary depending on the definition of the study population. For these subtypes, standardized incidence ratios calculated using general population statistics could be misleading. Moreover, etiological arguments should be used to inform methodological choices during study design.
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| 2. |
- Houle, Brian, et al.
(författare)
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Social patterns and differentials in the fertility transition in the context of HIV/AIDS : evidence from population surveillance, rural South Africa, 1993-2013
- 2016
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Ingår i: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Literature is limited on the effects of high prevalence HIV on fertility in the absence of treatment, and the effects of the introduction of sustained access to antiretroviral therapy (ART) on fertility. We summarize fertility patterns in rural northeast South Africa over 21 years during dynamic social and epidemiological change. Methods: We use data for females aged 15-49 from the Agincourt health and socio-demographic surveillance system (1993-2013). We use discrete time event history analysis to summarize patterns in the probability of any birth. Results: Overall fertility declined in 2001-2003, increased in 2004-2011, and then declined in 2012-2013. South Africans showed a similar pattern. Mozambicans showed a different pattern, with strong declines prior to 2003 before stalling during 2004-2007, and then continued fertility decline afterwards. There was an inverse gradient between fertility levels and household socioeconomic status. The gradient did not vary by time or nationality. Conclusions: The fertility transition in rural South Africa shows a pattern of decline until the height of the HIV/AIDS pandemic, with a resulting stall until further decline in the context of ART rollout. Fertility patterns are not homogenous among groups.
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| 3. |
- Leijon, Matti, et al.
(författare)
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The longitudinal age and birth cohort trends of regular exercise among adults aged 16-63 years in Sweden: a 24-year follow-up study
- 2015
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Ingår i: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The aim of this study is to analyze longitudinally, based on four measurements at intervals of eight years, the annual effect of age group and birth cohort on regular exercise in the Swedish population from 1980-1981 to 2004-2005. Methods: We followed a randomly drawn subsample of individuals aged 16-63 years, interviewed by professional interviewers, from the Swedish Annual Level of Living Survey. We applied a mixed model with a random intercept and a random slope in order to analyze the annual effects. Results: The prevalence of regular exercise increased annually by 0.3 % among men and 0.7 % among women. For every one-unit increase in BMI, the odds of regular physical activity decreased by 6 % among men and 5 % among women. While the female birth cohorts all increased over time the male birth cohorts showed a different pattern, as only the three oldest birth cohorts (1926-1933, 1934-1941, 1942-1949) showed an increase in regular exercise. The three youngest birth cohorts (1958-1965, 1966-1973, 1974-1981) instead showed a decreased prevalence of regular exercise. There was an inverse relationship between regular exercise and age, although the differences between age groups tended to decrease over time. Differences related to educational level increased over time as the prevalence of exercise among those with higher educational attainment increased more than among those with lower educational attainment. The most dramatic relative increase in exercise over time (almost two-fold) was found among those who were obese or who reported a poor health status. Conclusions: The prevalence of regular exercise increased in all studied sub-groups. However, the increased difference related to education level is worrying. To reduce the risk for ill health in these groups, there is a need for targeted interventions.
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