Variability and determinants of total homocysteine concentrations in plasma in an elderly population

The variability of plasma total homocysteine (tHcy) was examined in 96 individuals over a 1-yr period. Blood tHcy concentrations varied from 7.1 micromol/L in the bottom quintile to 14.5 micromol/L in the top quintile. The mean tHcy was 10.4 micromol/L, the between-person SD was 2.5 micromol/L, and the within-person SD was 0.93 micromol/L. There was little seasonal variation, and the reliability coefficient was 0.88. Mean tHcy concentrations were inversely related to mean plasma folate (r = -0.36) and vitamin B12 (r = -0.35) concentrations. Median tHcy concentrations were approximately 1 micromol/L higher in men than in women and in older (70 to 74 years) than in younger (65 to 69 years) individuals and higher in those with the TT and CT genotypes for the methylenetetrahydrofolate reductase polymorphism than in those with the CC genotype (10.7 and 10.6 vs 9.6 micromol/L). Epidemiological studies based on single tHcy measurements may underestimate the magnitude of any risk associations with disease by 10-15%.

Interrelation of vitamin C, infection, haemostatic factors, and cardiovascular disease

OBJECTIVE

To examine the hypothesis that the increase in fibrinogen concentration and respiratory infections in winter is related to seasonal variations in vitamin C status (assessed with serum ascorbate concentration).

DESIGN

Longitudinal study of individuals seen at intervals of two months over one year.

SETTING

Cambridge.

SUBJECTS

96 men and women aged 65-74 years living in their own homes.

MAIN OUTCOME MEASURES

Haemostatic factors fibrinogen and factor VIIC; acute phase proteins; respiratory symptoms; respiratory function.

RESULTS

Mean dietary intake of vitamin C varied from about 65 mg/24 h in winter to 90 mg/24 h in summer; mean serum ascorbate concentration ranged from 50 mumol/l in winter to 60 mumol/l in summer. Serum ascorbate concentration was strongly inversely related to haemostatic factors fibrinogen and factor VIIC as well as to acute phase proteins but not to self reported respiratory symptoms or neutrophil count. Serum ascorbate concentration was also related positively to forced expiratory volume in one second. An increase in dietary vitamin C of 60 mg daily (about one orange) was associated with a decrease in fibrinogen concentrations of 0.15 g/l, equivalent (according to prospective studies) to a decline of approximately 10% in risk of ischaemic heart disease.

CONCLUSION

High intake of vitamin C has been suggested as being protective both for respiratory infection and for cardiovascular disease. These findings support the hypothesis that vitamin C may protect against cardiovascular disease through an effect on haemostatic factors at least partly through the response to infection; this may have implications both for our understanding of the pathogenetic mechanisms in respiratory and cardiovascular disease and for the prevention of such conditions.

Seasonal variation in 25-hydroxyvitamin D and parathyroid hormone concentrations in healthy elderly people

Seasonal variation in serum 25-hydroxyvitamin D and parathyroid hormone concentration was examined longitudinally in 96 community-dwelling men and women aged 65-74 years. Mean 25-hydroxyvitamin D concentration was lowest in winter (22.7 mmol/l) and highest in summer (35.4 mmol/l); mean parathyroid hormone concentration was highest in winter (3.55 pmol/l) and lowest in summer (3.24 pmol/l): these seasonal variations were highly significant (p < 0.0001). Parathyroid hormone concentrations were inversely related to 25-hydroxyvitamin D concentrations (p < 0.0001). Seasonal variation of 25-hydroxyvitamin D and parathyroid hormone concentration is marked in older healthy adults in Britain. Even in summer, mean 25-hydroxyvitamin D concentrations are low; maintaining more optimal vitamin D levels in the general population may have clinical and public health benefits.

Assessment of cardiotocographs

In recent years advances in medical electronic equipment for monitoring, diagnosis and treatment of patients have led to a large increase in the number and variety of instrumentation available to the medical profession. There is a considerable amount of duplication of equipment and in the absence of readily available information buyers are unlikely to make informed decisions about the ideal instrument for their particular circumstances. One method of increasing the users' awareness is a comparative, independent assessment of equipment, with the results disseminated to the interested parties. This paper describes the essential qualities of cardiotocographs: how they are assessed as part of the UK Department of Health's evaluation programme and the measures to inform users of the latest evaluation information.

Factors associated with hypothermia in patients admitted to a group of inner city hospitals

In a case-control study of factors contributing to hypothermia all fourteen patients (mean age 80 years) admitted to hospital with hypothermia after being found ill indoors also had some other serious illness. They were more likely than control patients to have been alone when taken ill (93 vs 39% of controls), to live alone (86 vs 43%), and to have been found on the floor (79 vs 14%). They were less likely to have been wearing more than indoor clothing (0 vs 50%), or to have had heating on when found (50 vs 89%), but 93% of patients in both groups had heating available. Healthy young adult volunteers who lay immobile on the ground in air at 5 degrees C lightly clothed cooled progressively by 0.57 degrees C (SD 0.32) (rectal T degrees) in 90 min despite doubling of metabolic rate. With better insulation in bed, core temperature stabilised within 90 min, and when they were in an armchair it fell slowly, with no increase in metabolic rate in either case. The findings suggest that hypothermia indoors resulted largely from collapse due to illness when the patient was alone lightly clothed and not in bed. Eight hypothermic patients found outside (in December and January) were younger (mean age 60 years) than the fourteen found indoors; six of these were chronic alcoholics or acutely intoxicated, and six lacked, or had wandered from, a fixed home.