Vitamin D Status of an Outpatient Clinic Population

Abstract

Vitamin D insufficiency contributes to bone loss and fracture risk. Low 25-hydroxyvitamin D (25OHD) levels are common in elderly people and in housebound and hospitalized patients. This study was conducted to assess wintertime 25OHD levels in relation to self-reported vitamin D supplement use in an outpatient thyroid clinic population. We assessed the medical history, vitamin D intake from milk and supplements, and serum 25OHD levels in 231 women and 41 men who attended a Thyroid Clinic between January and March, 1999. Of the 272 outpatients, 13.6% had 25OHD levels <40 nmol/l and 53.3% had levels below 80 nmol/l. Fewer than 15% of the patients consumed more than 200 IU per day of vitamin D from milk. Vitamin D supplement use was a positive determinant of serum 25OHD concentration (P < 0.001). For example, among the largest homogenous subset of patients, Caucasian women (n = 137), 30% of the unsupplemented women, and 65% of those taking 400 lU/day of vitamin D had levels of 25OHD as high as 80 nmol/l. Other significant determinants of 25OHD levels were race, weight, milk intake, and recent southern travel. Thyroid disorder, serum TSH level, and age were not predictors of serum 25OHD concentration. In conclusion, at their current dietary vitamin D intake levels, most patients at this latitude will need vitamin D supplements in the wintertime.

Effect of Vitamin D supplement use on serum concentrations of total 25OHD levels in elderly women

“…Seasonal variation in serum 25OHD levels has also been reported in our study population [19]. Another recent study reported that about 13.6% of the population (age range 18-86 years) attending a Boston outpatient clinic had serum 25OHD levels less than 16 ng/ml in winter time [20]. They also reported that Vitamin D supplementation is a positive determinant of serum 25OHD concentration with about 65% of those taking a Vitamin D supplement having serum 25OHD levels as high as 32 ng/ml.…”

Effect of calcium and vitamin D supplementation on bone mineral density in women aged 65–71 years: a 3-year randomized population-based trial (OSTPRE-FPS)

“…Vitamin D deficiency is common in the elderly since the capacity of the skin to synthesize provitamin decreases with age [6]. Low vitamin D status is prevalent in elderly women living in northern latitudes [7], but this deficiency can also be detected in young adults in northern Europe [8] and in the housebound elderly [9]. It is believed that in order to achieve an optimal vitamin D level of >75 nmol/l one should consume between 800 and 1,000 IU of vitamin D everyday [10].…”

Rickets in Healthy Adolescents in Van, the Eastern of Turkey

“…They found that overall, 52% of the students were vitamin D-insufficient; the proportion of insufficiency was 65% in the winter and 40% at the end of the summer. In our study, while the number of cases with rickets and consisted of 272 patients from England, a serum level of 25(OH)D3 was found low (<16 ng/dL) in 13.6% of patients (20).…”

“…Insufficient intake of calcium and vitamin D with nourishments and excessive consumption of carbonated drinks are determined to be risk factors for developing rickets in adolescents with symptomatic rickets (6). An 85% of cases in which a moderate and severe vitamin D insufficiency was determined had an intake of vitamin D less than 200 IU (20).…”