How good is probabilistic record linkage to reconstruct reproductive histories? Results from the Aberdeen children of the 1950s study

BACKGROUND: Probabilistic record linkage is widely used in epidemiology, but studies of its validity are rare. Our aim was to validate its use to identify births to a cohort of women, being drawn from a large cohort of people born in Scotland in the early 1950s. METHODS: The Children of the 1950s cohort includes 5868 females born in Aberdeen 1950–56 who were in primary schools in the city in 1962. In 2001 a postal questionnaire was sent to the cohort members resident in the UK requesting information on offspring. Probabilistic record linkage (based on surname, maiden name, initials, date of birth and postcode) was used to link the females in the cohort to birth records held by the Scottish Maternity Record System (SMR 2). RESULTS: We attempted to mail a total of 5540 women; 3752 (68%) returned a completed questionnaire. Of these 86% reported having had at least one birth. Linkage to SMR 2 was attempted for 5634 women, one or more maternity records were found for 3743. There were 2604 women who reported at least one birth in the questionnaire and who were linked to one or more SMR 2 records. When judged against the questionnaire information, the linkage correctly identified 4930 births and missed 601 others. These mostly occurred outside of Scotland (147) or prior to full coverage by SMR 2 (454). There were 134 births incorrectly linked to SMR 2. CONCLUSION: Probabilistic record linkage to routine maternity records applied to population-based cohort, using name, date of birth and place of residence, can have high specificity, and as such may be reliably used in epidemiological research

Statin use is not associated with future long-term care admission - extended follow-up of two randomised controlled trials

Background: Statins have been associated with later life, long-term care admission in observational studies. However, by preventing vascular events, statins may also prevent or delay admission. We wished to determine statin and long-term care admission associations in a randomised controlled trial context, and describe associations between long-term care admission and other clinical and demographic factors. Methods: We used extended follow-up of two randomised trial populations, using national data to assign the long-term care admission outcome, and included individuals screened or recruited to two large randomised trials of pravastatin 40 mg daily—the West of Scotland Coronary Prevention Study (WOSCOPS) and the pravastatin in elderly individuals at risk of vascular disease (PROSPER) study. We described univariable and multivariable analyses of potential predictors of long-term care admission with corresponding survival curves of incident long-term care admission and analyses adjusted for competing risk. Results: In total 11,015 (10%) of the trial participants were admitted to long-term care. There was no difference between participants in the statin or placebo arms of either trial in regard to admissions to long-term care. On multivariable analyses, independent associations with incident long-term care admission in the PROSPER trial were age (hazard ratio [HR] 1.06 per year, 95% confidence interval [CI] 1.03–1.09) and male sex (HR 0.72, 95% CI 0.53–0.99). In the WOSCOPS, age (HR 1.12 per year, 95% CI 1.10–1.13) and increasing social deprivation (HR 1.05, 95% CI 1.03–1.08) were associated with incident long-term care admission. Conclusion: We did not demonstrate an association between historical statin use and future long-term care admission. The strongest associations with incident long-term care admission were non-modifiable factors of age, sex and socioeconomic deprivation