Possible value of fluorescent lighting in the prevention of vitamin D deficiency in the elderly

Oral vitamin D and ultraviolet radiation for the prevention of vitamin D deficiency in the elderly

Different methods for the prevention and treatment of vitamin D deficiency were studied in 42 institutionalized elderly people. One group received ultraviolet radiation (UVR) on a large area of the body surface once a week for three months. The results were compared with those in groups receiving either 450 IU vitamin D2 together with 420 mg calcium daily, 420 mg calcium alone, or no treatment. A significant increase in serum 25-hydroxyvitamin D was obtained with UVR. A similar increase was obtained with oral vitamin D2. A small but significant decrease in serum alkaline phosphatase was observed in subjects receiving vitamin D and calcium or calcium alone. No effects on serum phosphate, urinary cyclic adenosine monophosphate and urinary calcium were seen. Though brief UVR at one-week intervals is an efficient and safe method for prevention of vitamin D deficiency in the elderly, it is in our experience time-consuming for the ward staff and thus less convenient than oral vitamin D supplementation.

Differences in vitamin D status between countries in young adults and the elderly

PURPOSE

To compare vitamin D status between countries in young adults and in the elderly.

MATERIALS AND METHODS

Reports on vitamin D status (as assessed by serum 25-hydroxyvitamin D) from 1971 to 1990 were reviewed. Studies were grouped according to geographic regions: North America (including Canada and the United States); Scandinavia (including Denmark, Finland, Norway, and Sweden); and Central and Western Europe (including Belgium, France, Germany, Ireland, The Netherlands, Switzerland, and the United Kingdom).

RESULTS

Vitamin D status varies with the season in young adults and in the elderly, and is lower during the winter in Europe than in both North America and Scandinavia. Oral vitamin D intake is lower in Europe than in both North America and Scandinavia. Hypovitaminosis D and related abnormalities in bone chemistry are most common in elderly residents in Europe but are reported in all elderly populations.

CONCLUSIONS

The vitamin D status in young adults and the elderly varies widely with the country of residence. Adequate exposure to summer sunlight is the essential means to ample supply, but oral intake augmented by both fortification and supplementation is necessary to maintain baseline stores. All countries should adopt a fortification policy. It seems likely that the elderly would benefit additionally from a daily supplement of 10 micrograms of vitamin D.

Vitamin D status among patients with fractured neck of femur in Hong Kong

Vitamin D deficiency leads to secondary hyperparathyroidism initially and then to mild osteomalacia, both of which conditions may be aymptomatic and may predispose to bone fracture. To assess the importance of vitamin D deficiency in predisposing to fractured neck of femur, we studied the vitamin D status, dietary intake and socio-economic characteristics in 69 patients with fractured neck of femur (group A), 28 normal subjects with age above 60 (group B), and 101 normal volunteers (group C). Patients with fractured neck of femor had significantly lower levels of serum 25-hydroxy-cholecalciferol compared with subjects of groups B and C. There is no statistically significant difference in other biochemical parameters, including calcium, phosphate, and alkaline phosphatase. Patients with fractured neck of femur and with 25-hydroxycholecalciferol below 20 ng/mL were characterized by a home-bound and/or institutionalized life-style, smaller living place, and limited access to open space. To conclude, hypovitaminosis D is a common problem among elderly patients with fractured neck of femur in Hong Kong. The fact that such vitamin D deficiency is associated with muscle weakness may contribute to falls, and thus indirectly account for an increased rate of hip fractures over the normal control.

Measurement of blood levels of 7-dehydrocholesterol in man by high-performance liquid chromatography

A high-performance liquid chromatography procedure was established to measure 7-dehydrocholesterol (7DHC) in the blood. Interference studies were performed using 20 similar compounds likely to give analytical errors. 7DHC was extracted with a methanol chloroform mixture. Extraction recoveries were reproducible and acceptable, with low methodological variations from batch-to-batch. Results show that 7DHC is not detectable in the blood, contrary to the previous reports. Possible explanations for its absence in the blood are: (1) it is confined to the skin and is not present in the blood in this form; (2) because the molecule is labile, it is destroyed by the methods applied; (3) previous reports on 7DHC levels were based on non-specific methods.

Tanning, protection against sunburn and vitamin D formation with a UV-A 'sun-bed'

There are many types of sun-beds, sun-benches and sun-panels containing fluorescent tubes which, because of their predominantly UV-A emission, are advertised to the public as a means of obtaining a tan without sunburn. This study reports the effects of a sun-bed on skin colour, on the protection afforded against sunburn, and on vitamin D formation. Side-effects are also recorded. It was shown that the sun-bed emits mainly UV-A but very little UV-B and some tanning occurred in most subjects. However, no correlation was observed between the subjects' stated ability to tan and the degree of pigmentation achieved at the end of the treatment. Most subjects also had itching and erythema, and three had polymorphic light eruption. Although very little UV-B irradiation was present, a significant increase in serum levels of 25-hydroxyvitamin D occurred, and possible explanations of this surprising finding are discussed. While the sun-bed proved popular with the subjects, only a modest tan was achieved and the incidence of side-effects appeared to limit the value of this type of appliance, especially with regard to the prevention of vitamin D deficiency.

Commercially available sun lamps and vitamin D formation

Four commercially available, medium pressure mercury sun lamps were used to assess their effects on promoting vitamin D synthesis in the skin. It was found that all the lamps studied had vitamin D synthesizing spectral wavelengths and caused an increase in the serum concentrations of 25-hydroxyvitamin D. However, the ultraviolet and visible irradiance measurements showed that a considerable proportion of the ultraviolet radiation was below 290 nm. It was not surprising, therefore, to find that these lamps caused adverse skin reactions. While a useful rise in vitamin D production can be obtained with these sun lamps, the difficulty involved in avoiding skin reaction limits their usefulness. Such lamps are unlikely to provide a safe practical routine method for the prevention of vitamin D deficiency in the home.