Ageing and mortality. Results from the Zutphen-Study

The link between competing death risks and the change of risk factor levels over time has been analysed using data from the Zutphen-Study and the model of Manton&Stallard. The Zutphen-cohort consists of 878 men, initially with te ages of 40-59 years, that have been followed since 1960. The model of Manton&Stallard describes the change of the distribution of the risk factor levels of a cohort over time taking into account mortality and the change of levesl within individuals. The hazard function used is similar to the one used in the Cox proportional hazards model. For almost the same combinations of risk factors and causes of death significant effects have been found as in Cox analyses. However, using current instead of baseline risk factor measurement values result in smaller effects probably due to medication (for total cholesterol and systolic bloodpressure) or in larger effects probably due to a reverse causal relation (for BMI and lung cancer). The most interesting and striking rsults were found with respect to the risk factor changes over age. We found positive age-trends for all risk factors (although non-significant for cholesterol), whereas the results of simple regression analyses were not that clear. More specific results relate to the interactions with respect to the deterministic and random changes. The results of the analyses will be used for the further development of the chronic diseases modelling tools. That means, the refinement of the modelling of the changes of the risk factors mentioned above over age, and the relation (interaction) between thes changes