Hazard ratios for the initial event in the vaccine group, in comparison with the placebo group, were estimated by means of a Cox proportional-hazards regression model. Vaccine efficacy was calculated as 1 minus the hazard ratio, times 100.1,5,22 When the proportional-hazards assumption was violated, the Cox model was stratified based on the calendar year of recruitment and the baseline CD4+ count, and data were analyzed for the first 12 weeks separately. On October 31 Data from individual information were censored, 2007, or the date of loss or loss of life to follow-up, whichever came first. We used bad binomial regression versions to estimate incidence-price ratios for multiple-event analyses.Wharton, F.R.C.Path., Paul G. Ince, M.D., Gillian Forster, B.Sc., Fiona E. Matthews, Ph.D., and Carol Brayne, M.D. For the Medical Analysis Council Cognitive Function and Ageing Study: Age group, Neuropathology, and Dementia During the 20th century, appeal to in the dementias centered on specific disorders defined by criteria which were developed for sufferers who had starting point of dementia prior to the age of 65 years, which had become considered by many as distinct from late-onset dementia pathologically.1 In the next half of that hundred years, the distinction between early-onset and late-onset dementias was challenged by the realization that the hallmarks of Alzheimer’s disease in older people had been indistinguishable from those in younger people with Alzheimer’s disease.2 Population epidemiologic research of dementia possess revealed a relentless rise in the incidence of dementia into old age,3 and clinically diagnosed Alzheimer’s disease is known as to be the major subtype of dementia.4 The role of Alzheimer’s disease in very old people has become less clear because the contribution of vascular and other pathological changes has been recognized.5,6 Study in dementia is driven by the expectation that understanding the genetic and molecular results underlying clinical subtypes of dementia can lead to major prevention strategies for the whole population.7 The best demographic change may be the increasing number of persons over 85 years of age, in whom most cases of dementia will happen.