Contributions of vitamin D intake and seasonal sunlight exposure to plasma 25-hydroxyvitamin D concentration in elderly women

Abstract

We investigated the contributions (1.00-8.03 micrograms/d, or 40-321 IU/d) of vitamin D intake and seasonal sunlight exposure to plasma 25(OH)D in 59 healthy women aged 70-97 y with a mean total vitamin D intake of 8.58 micrograms/d (343 IU/d). In the summer and winter, each subject had a fasting blood measurement and assessments of vitamin D intake and sunlight exposure. Vitamin D intake was significantly correlated with plasma 25(OH)D in the summer (r = 0.52, P < 0.01) and winter (r = 0.63, P < 0.01). The influence of sunlight exposure measured in the summer on the 25(OH)D concentration was dependent on the vitamin D intake. In subjects with lower vitamin D intakes (1.00-8.03 micrograms/d, or 40-321 IU/d), the wintertime 25(OH)D concentrations of those with low and high sunlight exposure were comparable. In subjects with higher vitamin D intakes (11.15-28.68 micrograms/d, or 446-1147 IU/d), however, the wintertime 25(OH)D concentrations of those with high sunlight exposure were lower than those with lower exposure [63.8 +/- 3.9 and 80.6 +/- 6.7 nmol/L, respectively, P = 0.066; P (intake by exposure interaction) < 0.05]. This suggests that the contribution of vitamin D intake to plasma 25(OH)D concentration may be influenced by sunlight exposure.

Change in plasma levels of vitamin D after consumption of cod-liver and fresh cod-liver oil as part of the traditional north Norwegian fish dish “Molje”

“…The correlation between the estimated daily vitamin D intake and 25(OH)D blood concentrations has been shown to be significant among subjects with low sun exposure (23,24). In our study, no such data was collected.…”

Vitamin D intake is low and hypovitaminosis D common in healthy 9− to 15-year-old Finnish girls

“…In a Norwegian study the Spearman correlation coef®cients between FFQ and 7-day food recording for vitamin D was even lower 0.14 (Andersen et al, 1995a). The correlation between S-25(OH)D and dietary intake of vitamin D has been 0.13 to 0.80 in previous studies (Lips et al, 1987;Krall et al, 1989;Salamone et al, 1993). In the present study at baseline, there was a statistically signi®cant but weak correlation between S-25(OH)D and intake of vitamin D as assessed by FFQ, but not by food recording.…”

“…Currently vitamin D de®ciency occurs in elderly people in Europe (Heikinheimo et al, 1996;Lips et al, 1996) and it may be an important risk factor for osteoporotic hip fractures (Lips et al, 1987), as implied by the fact that supplementation with vitamin D and calcium reduces the risk of hip fractures and other nonvertebral fractures among elderly women (Chapuy et al, 1992;Dawson-Hughes et al, 1997). Many studies have shown a signi®cant correlation between the dietary vitamin D intake and the serum 25-hydroxyvitamin D [S-25(OH)D] concentration in the elderly (Lips et al, 1987;Krall et al, 1989;Salamone et al, 1993;Thomas et al, 1998). Vitamin D from the diet is clearly important in the northern countries like Finland (Lamberg-Allardt, 1984).…”

Vitamin D deficiency: a concern in premenopausal Bangladeshi women of two socio-economic groups in rural and urban region

“…Vitamin D deficiency is very likely to happen due to increasing demand at rapid growth in fetal life, infancy, early childhood and puberty, during pregnancy, lactation and in the elderly (Alfaham et al, 1995). Physiological factors, lifestyle and environmental characteristics may be the cause of vitamin D deficiency (Webb et al, 1990;Salamone et al, 1993). Serum 25-hydroxyvitamin D (25-OHD) is used as an index of vitamin D status (van den Berg, 1993).…”