Representativeness in population-based studies of older adults: five waves of cross-sectional examinations in the Gothenburg H70 Birth Cohort Study

Abstract

ObjectivesTo describe representativeness in the Gothenburg H70 1930 Birth Cohort Study.DesignRepeated cross-sectional examinations of a population-based study.SettingGothenburg, Sweden.ParticipantsAll residents of Gothenburg, Sweden, born on specific birth dates in 1930 were invited to a comprehensive health examination at ages 70, 75, 79, 85 and 88. The number of participants at each examination was 524 at age 70, 767 at age 75, 580 at age 79, 416 at age 85, and 258 at age 88.Primary outcome measuresWe compared register data on sociodemographic characteristics and hospital discharge diagnoses between participants and (1) refusals, (2) all same-aged individuals in Gothenburg and (3) all same-aged individuals in Sweden. We also compared mortality rates between participants and refusals.ResultsRefusal rate increased with age. At two or more examination waves, participants compared with refusals had higher educational level, more often had osteoarthritis, had lower mortality rates, had lower prevalence of neuropsychiatric, alcohol-related and cardiovascular disorders, and were more often married. At two examination waves, participants compared with same-aged individuals in Gothenburg had higher education and were more often born in Sweden. At two examination waves or more, participants compared with same-aged individuals in Sweden had higher education, had higher average income, less often had ischaemic heart disease, were less often born in Sweden and were more often divorced.ConclusionsParticipants were more similar to the target population in Gothenburg than to refusals and same-aged individuals in Sweden. Our study shows the importance of having different comparison groups when assessing representativeness of population studies, which is important in evaluating generalisability of results. The study also contributes unique and up-to-date knowledge about participation bias in these high age groups.

Prevalence of Possible Idiopathic Normal Pressure Hydrocephalus in Sweden

“…One previous study investigating representativeness among 70-year-olds born 1930 in the H70 studies showed that participants had higher income, less neuropsychiatric and cerebrovascular diseases than same-aged individuals in Gothenburg. 44 However, education level and the proportion of individuals born in Sweden did not differ. 44 In addition, when comparing characteristics between the MRI sample and those who did not participate in the MRI examination, those who participated had higher education levels, higher scores on MMSE, and less often dementia.…”

“… 44 However, education level and the proportion of individuals born in Sweden did not differ. 44 In addition, when comparing characteristics between the MRI sample and those who did not participate in the MRI examination, those who participated had higher education levels, higher scores on MMSE, and less often dementia. 31 There were no differences regarding the proportion of women 31 or individuals born in Sweden.…”

Using magnetic resonance imaging to measure head muscles: An innovative method to opportunistically determine muscle mass and detect sarcopenia

“…This is a comprehensive population study examining birth cohorts of older people in Gothenburg 13 . This study comprised one cohort born in 1944 (examined in 2014–2016 with a response rate of 72%; n = 1203) 13,14 …”

“…13 This study comprised one cohort born in 1944 (examined in 2014-2016 with a response rate of 72%; n = 1203). 13,14 The participants were interviewed face to face, providing information on different topics: comorbidity, lifestyle behaviours, nutrition, functional performance, medications, cohabitation and education level. From the total of 1203 persons, we included 791 who had MRI images available, and from them, 251 individuals did not have good visualization of either the tongue or the masseter.…”

Willingness to participate in a personalized health cohort – Insights from the Swiss Health Study pilot phase

“…(2) Sampling in a cohort study or: the issue of representativeness Compared to the general socio-demographic composition of Switzerland, the SHeS-pilot study showed a tendency towards higher participation of better educated and high-income citizens, an issue typical for health cohorts (50,51) that leads to lower diversity regarding socio-economic status, migration experience or ethnic origin. Also, long-lasting cohort studies face the challenge of attrition bias in that the characteristics of those leaving the study differ from those remaining in the study (52).…”