- The sustainability of publicly funded health care systems is an issue for governments around the world. The economic climate limits governments' fiscal capacity to continue to devote an increasing share of public funds to health care. Meanwhile the demands for health care within populations continue to increase. Planning the future requirements for health care is typically based on applying current levels of health service use by age to demographic projections of the population. But changes in age-specific levels of health over time would undermine this 'constant use by age' assumption. We use representative Canadian survey data (Canadian Community Health Survey) covering the period 2001-2012, to identify the separate trends in demography (population ageing) and epidemiology (population health) on self-reported health. We propose an approach to estimating future health care requirements that incorporates cohort trends in health. Overall health care requirements for the population increase as the size and mean age of the population increase, but these effects are mitigated by cohort trends in health-we find the estimated need for health care is lower when models account for cohort effects in addition to age effects.