Actuarial projections allow predicting the likely evolution of the population and therefore the future number of individuals included in each cell of the model. Future health expenditure is determined by multiplying the average costs by the projected number of individuals included in each cell. More advanced cohort-based models take into account trends in disabilities as w'ell as factors influencing epidemiologic trends such as, individual behaviour and exposure to risks factors (e.g. smoking, obesity, hypertension and cholesterol).