Advancing age is characterized by impairment in the function of the many regulatory processes that provide functional integration between cells and organs. Therefore, there may be a failure to maintain homeostasis under conditions of physiolog ical stress. The reduced homeostatic ability affects different regulatory systems in different subjects, thus explaining at least partly the increased interindividual variability occurring as people get older. Important pharmacokinetic and pharmacodynamic changes occur with advancing age. Pharmacokinetic changes include a reduction in renal and hepatic clearance and an increase in volume of distribution of lipid soluble drugs (hence prolongation of elimination half-life) whereas pharmacodynamic changes involve altered (usually increased) sensitivity to several classes of drugs such as anticoagulants, cardiovascular and psychotropic drugs. This review focuses on the main age-related physiological changes affecting different organ systems and their implications for pharmacokinetics and pharmacodynamics of drugs.

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vitamin D supplementation, in fallers with vitamin D insufficiency, has a significant beneficial effect on functional performance, reaction time and balance, but not muscle strength. This suggests that vitamin D supplementation improves neuromuscular or neuroprotective function, which may in part explain the mechanism whereby vitamin D reduces falls and fractures.

ABSTRACT

There is widespread evidence both of the exclusion of older people from clinical research, and of under-recruitment to clinical trials. This review and opinion piece provides practical advice to assist researchers both to adopt realistic, achievable recruitment rates and to increase the number of older people taking part in research. It analyses 14 consecutive recently published trials, providing the number needed to be screened to recruit one older participant (around 3:1), numbers excluded (up to 49%), drop out rates (5-37%) and whether the planned power was achieved. The value of planning and logistics are outlined, and approaches to optimising recruitment in hospital, primary care and care home settings are discussed, together with the challenges of involving older adults with mental incapacity and those from minority groups in research. The increasingly important task of engaging older members of the public and older patients in research is also discussed. Increasing the participation of older people in research will improve the generalisability of research findings and inform best practice in the clinical management of the growing older population.

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Age-related decline in allocentric (viewer-independent) spatial memory is seen across species. We employed a virtual reality analogue of the Morris Water Maze to study the effect of healthy ageing on neural activity during allocentric spatial memory using functional magnetic resonance imaging. Voxel-based morphometry was used to ascertain hippocampal volumetric integrity. A widespread neural network comprising frontal, parietal, occipital, thalamic, and cerebellar regions was activated in young and older adults, but only young adults significantly activated bilateral hippocampus and left parahippocampus, as well as right frontal pole and dorso-lateral prefrontal cortex (DLPFC) during encoding and right DLPC during retrieval. Hippocampal grey matter volume was unchanged in older adults; however, prefrontal and parahippocampal functional attenuation was accompanied by volumetric reduction. We conclude that the decline in allocentric spatial memory with age is associated with attenuated hippocampal function, as well as compromised function and structure of prefrontal and parahippocampal regions.

BACKGROUND:Clinical trials show benefit from lowering systolic blood pressure (SBP) in people ≥80 years of age, but nonrandomized epidemiological studies suggest lower SBP may be associated with higher mortality. This study aimed to evaluate associations of SBP with allcause mortality by frailty category >80 years of age and to evaluate SBP trajectories before death. METHODS:A population-based cohort study was conducted using electronic health records of 144 403 participants ≥80 years of age registered with family practices in the United Kingdom from 2001 to 2014. Participants were followed for ≤5 years. Clinical records of SBP were analyzed. Frailty status was classified using the e-Frailty Index into the categories of fit, mild, moderate, and severe. All-cause mortality was evaluated by frailty status and mean SBP in Cox proportionalhazards models. SBP trajectories were evaluated using person months as observations, with mean SBP and antihypertensive treatment status estimated for each person month. Fractional polynomial models were used to estimate SBP trajectories over 5 years before death. RESULTS:During follow-up, 51 808 deaths occurred. Mortality rates increased with frailty level and were greatest at SBP <110 mm Hg. In fit women, mortality was 7.7 per 100 person years at SBP 120 to 139 mm Hg, 15.2 at SBP 110 to 119 mm Hg, and 22.7 at SBP <110 mm Hg. For women with severe frailty, rates were 16.8, 25.2, and 39.6, respectively. SBP trajectories showed an accelerated decline in the last 2 years of life. The relative odds of SBP <120 mm Hg were higher in the last 3 months of life than 5 years previously in both treated (odds ratio, 6.06; 95% confidence interval, 5.40-6.81) and untreated (odds ratio, 6.31; 95% confidence interval, 5.30-7.52) patients. There was no evidence of intensification of antihypertensive therapy in the final 2 years of life. CONCLUSIONS:A terminal decline of SBP in the final 2 years of life suggests that nonrandomized epidemiological associations of low SBP with higher mortality may be accounted for by reverse causation if participants with lower blood pressure values are closer, on average, to the end of life. 2358 B lood pressure increases with age, and older people have a higher prevalence of hypertension. 1,2 Elevated systolic blood pressure (SBP) may be the most important risk factor for cardiovascular disease in older people. 3 Recently, several large clinical trials 4-9 have suggested that use of antihypertensive medications to lower blood pressure may reduce cardiovascular events and mortality in older adults. In HYVET (Hypertension in the Very Elderly Trial) 6 of antihypertensive therapy >80 years of age, lowering blood pressure was associated with 30% reduction in stroke, 21% reduction in all-cause mortality, and 64% reduction in heart failure. In SPRINT (Systolic Blood Pressure Intervention Trial), 7 in people ≥75 years of age, management of SBP to a target of <120 mm Hg was associated with 34% reduction in cardiovascular events and 33% reduction in all-cause mortality. Th...