The prevalence of human immunodeficiency virus (HIV) in the over 50 age group is increasing as a consequence of younger adults ageing with HIV, in addition to new diagnoses in later life. We conducted searches in MEDLINE for English language studies published between January 1984 and January 2010 using search terms 'HIV', 'AIDS', 'HIV testing' and 'HIV complications' and selected articles relevant to adults aged 50 years and over. The prevalence, natural history and complications of HIV infection and treatment in older adults are reviewed. In 2007 the Centers for Disease Control and Prevention in the United States reported that 16.8% of new diagnoses of HIV that year were in individuals aged over 50 years. Older adults are vulnerable to late or missed diagnosis, and poorer treatment outcomes, due to the misconception that they are not at risk. A heightened awareness of HIV as a possible diagnosis in older adults is becoming increasingly important. As the HIV population ages, the emergence of disease and treatment complications such as cardiovascular disease, osteoporosis and dementia are evident. Management of older adults with HIV and multiple co-morbidities presents challenges to infectious diseases physicians and geriatricians alike. Inclusion of older adults in future HIV clinical trials will help design healthcare models to provide for this growing population.

Despite comprehensive guidelines established by the European Global Initiative for Asthma and the U.S. National Asthma Education and Prevention Program on the diagnosis and management of asthma, its mortality in older adults continues to rise. Diagnostic and therapeutic problems contribute to older patients being inadequately treated. The diagnosis of asthma rests on the history and characteristic pulmonary function testing (PFT) with the demonstration of reversible airway obstruction, but there are unique problems in performing this test in older patients and in its interpretation. This review aims to address the difficulties in performing and interpreting PFT in older patients because of the effects of age-related changes in lung function on respiratory physiology. The concept of "airway remodeling" resulting in "fixed obstructive" PFT and the relevance of atopy in older people with asthma are assessed. There are certain therapeutic issues unique to older patients with asthma, including the increased probability of adverse effects in the setting of multiple comorbidities and issues surrounding effective drug delivery. The use of beta 2-agonist, anticholinergic, corticosteroid, and anti-immunoglobulin E treatments are discussed in the context of these therapeutic issues.

Orthostatic hypotension (OH) and vitamin B12 deficiency are common disorders in older people. Several case series have reported an association between vitamin B12 deficiency and OH. The effect of vitamin B12 replacement on this dysfunction has not been studied. We prospectively studied responses to head up tilt in patients over 70 years with vitamin B12 deficiency (intervention group) and compared their responses after replacement to those of matched patients with idiopathic OH and normal serum vitamin B12 concentrations (control group). Blood pressure (BP), heart rate (HR) and systemic vascular resistance (SVR) changes during orthostatic stress were evaluated using digital artery photoplethysmography. Eight patients and eight controls were studied. Initial head up tilt produced a mean BP decrease of 44/29 mmHg (s.e.m. 4/4 mmHg) in the intervention group and 33/12 mmHg (s.e.m. 3/2 mmHg) in the control group. Repeat head up tilt 6 months after vitamin B12 replacement produced a mean BP decrease of 15/9 mmHg (s.e.m. 5/2 mmHg) in the intervention group. The mean decrease in the control group was 30/12 mmHg (s.e.m. 2/2 mmHg). The difference in BP decreases between groups was statistically significant for both systolic and diastolic BP (p < 0.001 for both systolic BP and diastolic BP). Mean SVR in the intervention group decreased by 658 dynes/cm5/sec (s.e.m. 74 dynes/cm5/sec) during initial head up tilt. Mean SVR during repeat head up tilt decreased by 79 dynes/cm5/sec (s. e. m. 12 dynes/cm5/sec). Mean SVR in the control group decreased by 158 dynes/cm5/sec (s. e. m. 10 dynes/cm5/sec) during initial head up tilt and by 258 dynes/cm5/sec (s. e. m. 31 dynes/cm5/sec). The difference in SVR changes between groups was statistically significant (p = 0.02). We conclude that replacing vitamin B12 in older patients with vitamin B12 deficiency is associated with improved orthostatic tolerance to head up tilt.