Ascertainment of cancer in longitudinal research: The concordance between the Rotterdam Study and the Netherlands Cancer Registry.

Complete and accurate registration of cancer is needed to provide reliable data on cancer incidence and to investigate aetiology. Such data can be derived from national cancer registries, but also from large population-based cohort studies. Yet, the concordance and discordance between these two data sources remain unknown. We evaluated completeness and accuracy of cancer registration by studying the concordance between the population-based Rotterdam Study (RS) and the Netherlands Cancer Registry (NCR) between 1989 and 2012 using the independent case ascertainment method. We compared all incident cancers in participants of the RS (aged ≥45 years) to registered cancers in the NCR in the same persons based on the date of diagnosis and the International Classification of Diseases (ICD) code. In total, 2,977 unique incident cancers among 2,685 persons were registered. Two hundred eighty-eight cancers (9.7%) were coded by the RS that were not present in the NCR. These were mostly nonpathology-confirmed lung and haematological cancers. Furthermore, 116 cancers were coded by the NCR, but not by the RS (3.9%), of which 20.7% were breast cancers. Regarding pathology-confirmed cancer diagnoses, completeness was >95% in both registries. Eighty per cent of the cancers registered in both registries were coded with the same date of diagnosis and ICD code. Of the remaining cancers, 344 (14.5%) were misclassified with regard to date of diagnosis and 72 (3.0%) with regard to ICD code. Our findings indicate that multiple sources on cancer are complementary and should be combined to ensure reliable data on cancer incidence.

Risk factors for complicated grief in older adults.

BACKGROUND: Older adults grieving the death of a spouse have been found to have a higher risk of complicated grief compared with younger adults. OBJECTIVE: The study objective was to find out whether personal characteristics of the patient and the bereaved partner, or characteristics of the patient's illness, end-of-life care, and the nature of death are risk factors for complicated grief in older adults. METHODS: We performed a nested case-control study within the Rotterdam Study. We selected 100 couples of which one person had deceased and the other person experienced "complicated grief," and 100 control couples of which one person had deceased and the other person experienced "normal grief." Complicated grief was assessed with a 17-item Inventory of Complicated Grief (ICG). Determinants were assessed using several sources of information that were available for all participants of the Rotterdam Study. Additionally, medical files of the deceased were manually screened. Logistic regression analysis was performed. RESULTS: Only depression at baseline was significantly associated with complicated grief. Bereaved partners with depression at baseline had a higher risk of complicated grief compared to bereaved partners without depression (OR=3.48; 95% CI=1.40-8.68). CONCLUSIONS: Our results suggest that complicated grief in older adults is not clearly related to the circumstances of dying of the deceased partner. Preexisting conditions such as depression seem to be more important in explaining the occurrence of complicated grief.

Methods of data collection and definitions of cardiac outcomes in the Rotterdam Study.

The prevalence of cardiovascular diseases is rising. Therefore, adequate risk prediction and identification of its determinants is increasingly important. The Rotterdam Study is a prospective population-based cohort study ongoing since 1990 in the city of Rotterdam, The Netherlands. One of the main targets of the Rotterdam Study is to identify the determinants and prognosis of cardiovascular diseases. Case finding in epidemiological studies is strongly depending on various sources of follow-up and clear outcome definitions. The sources used for collection of data in the Rotterdam Study are diverse and the definitions of outcomes in the Rotterdam Study have changed due to the introduction of novel diagnostics and therapeutic interventions. This article gives the methods for data collection and the up-to-date definitions of the cardiac outcomes based on international guidelines, including the recently adopted cardiovascular disease mortality definitions. In all, detailed description of cardiac outcome definitions enhances the possibility to make comparisons with other studies in the field of cardiovascular research and may increase the strength of collaborations.