Does the Access to Sun Exposure Ensure Adequate Levels of 25-Hydroxyvitamin D?

To assess the prevalence of hypovitaminosis D, altered arterial blood pressure, and serum levels of glucose and lipids in community-dwelling women in the city of Ribeirão Preto, in the southeast of Brazil.

Methods

Thiswas a cross-sectional studyof women aged40-70years old.Calciumintake and level of sun exposure were assessed by means of a questionnaire. A blood sample was used to determine glucose, lipid profile and 25-hydroxyvitaminD(25[OH]D) concentration.

Results

Ninety-one women were enrolled (age = 54.2 ± 7.1 years). Themean serum 25(OH)D concentration was 25.7 ± 8.9 ng/mL. A total of 24 (26.4%) women had 25 (OH)D levels < 20 ng/mL. Seventy women (76.9%) had 25(OH)D levels < 30 ng/mL. Seventy-five women (90.4%) had inadequate calcium intake, and 61 women (67%) had appropriate sun exposure, 49 of whom (80.3%) had serum 25(OH)D levels < 30 ng/mL.

Conclusion

This study indicates that even in community-dwelling women, living in a city with high sun exposure, serum levels of 25(OH)D > 30 ng/ml are hardly reached. Thus, it is probable that other intrinsic factors besides sun exposure may regulate the levels of vitamin D.

Keywords:
Female Gender; 25-hydroxyvitamin D; vitamin D deficiency; sun exposure

Variable	Mean ± SD or n (%)
Age (years)	54.2 ± 7.1
BMI (kg/m²)	27.1 ± 4.8
25(OH)D (ng/mL)	25.7 ± 8.9
Calcium ion (mmol/L)	1.09 ± 0.05
Glucose (mg/dL)	90.4 ± 18.5
Total cholesterol (mg/dL)	187.1 ± 38.5
HDL-C (mg/dL)	46. 6 ± 11.8
Triglycerides (mg/dL)	115.2 ± 59.9
Creatinine (mg/dL)	0.80 ± 0.11
Diseases
Arterial hypertension	30 (32.9)
Hypothyroidism	11 (12.0)
Diabetes mellitus	7 (7.6)
Dyslipidemia	15 (16.4)
Other	25 (27.4)
None	28 (30.7)
Race
White	71 (78.0)
Mulatto/Black	20 (21.9)
Habits
Smoking (Yes)	11 (12.0)
Alcohol ingestion (Yes)	20 (22)
Physical activity
≤ 150 minute/week	76 (83.5)

	Vitamin D levels		p
	< 20 ng/mL (n= 24)	≥ 20 ng/mL (n= 67)	p
Arterial hypertension
Yes	7 (29.1%)	23 (34.3%)	0.64
No	17 (70.8%)	44 (65.6%)
Diabetes Mellitus
Yes	2 (8.3%)	5 (7.4%)	0.91
No	22 (91.6%)	62(92.5%)
Hypothyroidism
Yes	2 (8.3%)	9 (13.4%)	0.51
No	22 (91.6%)	58 (86.5%)
Alcohol ingestion
Yes	6 (25.0%)	14 (20.9%)	0.68
No	18 (75.0%)	53 (79.1%)
Smoking
Yes	5 (20.8%)	6 (8.9%)	0.13
No	19 (7.1%)	61 (91.0%)
Physical activity
None	2 (8.3%)	3 (4.6%)	0.14
≤ 150 minute/week	21 (87.5%)	48 (73.8%)
> 150 minute/week	1 (4.1%)	14 (21.5%)
Sun exposure
Adequate	17 (7.8%)	51 (7.2%)	0.53
Inadequate	7 (29.1%)	15 (2.7%)

	Vitamin D levels		p
	< 20 ng/mL (n= 24)Median (IQR)	≥ 20 ng/mL (n= 67)Median (IQR)	p
Age (years)	54.5 (47.5–57.0)	54.0 (49.0–60.0)	0.36
BMI (kg/m²)	28.9 (24.9–31.9)	26.4 (23.8–28.8)	0.15
Calcium ion (mmol/L)	1.09 (1.08–1.11)	1.1 (1.06–1.13)	0.97
Glucose (mg/dL)	93.5 (80.0–101.0)	89.3 (79.0–94.0)	0.55
Total cholesterol (mg/dL)	200.9 (176.5–218.0)	182.1 (158.0–203.0)	0.03
HDL-C (mg/dL)	44.3 (37.0–50.5)	47.5 (37.0–56.0)	0.30
Triglycerides (mg/dL)	129.5 (78.5–172.0)	110.1 (73.0–130.0)	0.25
Creatinine (mg/dL)	0.77 (0.70–0.83)	0.81 (0.70–0.90)	0.22

Variable	Odds Ratio	95% CI	p
Intercept	5.63	−14.09, 25.34	0.57
Sun exposure	0.36	−4.16, 4.87	0.88
Age	−0.03	−0.32, 0.26	0.83
Serum creatinine	28.11	10.36, 45.86	<0.01

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[1] Address for correspondence Ênio Luis Damaso, Rua Romeu Engrácia de Faria, 325, Apartment 34, Nova Aliança, Ribeirão Preto, SP, Brazil (e-mail: eniodamaso@yahoo.com.br).