The world population is ageing rapidly, but are older people of today in better health and function than the preceding generations? Surprisingly little is known about trends in health and function among the older populations, as well as determinants of healthy ageing. We will combine register-based data with a population-based longitudinal cohort study; the Tromsø Study. Information about dementia status for the study participants will be collected from hospital and nursing home records, we will follow individuals from young adulthood with measures of skills and health into midlife where biomarkers such as cholesterol level, blood glucose, lung function and self-reported life style habits have been collected, and into later life where health and functional capacity have been assessed. Two major topics will be investigated: First we will investigate trends in function and health among the old. Secondly, we will investigate modifiable determinants of healthy ageing at older ages.