Factors Associated with Vitamin D Deficiency and Inadequacy among Women of Childbearing Age in the United States

Table 1

Unadjusted and adjusted prevalence ratios (with 95% confidence intervals)* for vitamin D deficiency and inadequacy among women aged 20–44 years, NHANES 2003–2006, 𝑁 = 1,814.

Characteristic		Vitamin D deficiency		Vitamin D inadequacy
	𝑁	Unadjusted	Adjusted	Unadjusted	Adjusted
Demographic
Age (yrs)
20–27	651	1.00	1.00	1.00	1.00
28–34	540	0.98 (0.67–1.43)	1.02 (0.78–1.34)	0.94 (0.76–1.16)	0.92 (0.78–1.09)
35–44	623	1.17 (0.83–1.66)	1.19 (0.81–1.74)	1.09 (0.86–1.39)	1.10 (0.88–1.38)
Race/ethnicity
Non-Hispanic white	856	1.00	1.00	1.00	1.00
Non-Hispanic black	370	12.82 (7.31–22.47)	8.27 (5.06–13.50)	3.21 (2.50–4.13)	2.78 (2.14–3.61)
Mexican American	417	5.47 (2.85–10.51)	4.14 (2.20–7.78)	2.48 (1.93–3.18)	1.78 (1.36–2.33)
Other	171	5.36 (2.72–10.56)	5.44 (3.03–9.78)	2.48 (1.89–3.24)	2.25 (1.74–2.92)
Education
<High school diploma	393	1.00	1.00	1.00	1.00
High school graduate	383	0.69 (0.47–1.02)	1.06 (0.74–1.52)	0.78 (0.57–1.06)	1.03 (0.78–1.36)
>High school diploma	1,038	0.39 (0.29–0.55)	1.00 (0.75–1.34)	0.53 (0.42–0.66)	0.86 (0.67–1.10)
Pregnancy status
Currently pregnant	435	0.73 (0.37–1.45)	0.72 (0.41–1.26)	0.66 (0.45–0.96)	0.70 (0.49–1.00)
With a history of pregnancy	1,034	1.38 (0.99–1.92)	0.82 (0.57–1.16)	1.21 (0.93–1.59)	0.89 (0.71–1.11)
Never pregnant	345	1.00	1.00	1.00	1.00
Diet and supplementation
Milk consumption
Never	222	1.00	1.00	1.00	1.00
>0 to <1 time/day	730	0.54 (0.39–0.76)	0.77 (0.57–1.06)	0.94 (0.67–1.32)	0.87 (0.64–1.18)
≥1 time/day	862	0.20 (0.13–0.34)	0.34 (0.23–0.51)	0.59 (0.42–0.83)	0.56 (0.40–0.77)
Fish consumption
Never	573	1.00	1.00	1.00	1.00
>0 to <2 times/wk	1,134	0.79 (0.52–1.19)	0.75 (0.56–1.01)	1.00 (0.83–1.21)	1.01 (0.82–1.24)
≥2 times/wk	107	0.67 (0.33–1.34)	0.62 (0.31–1.23)	0.64 (0.40–1.03)	0.71 (0.48–1.05)
Dietary supplement use
Yes	943	0.30 (0.22–0.40)	0.57 (0.42–0.78)	0.55 (0.46–0.66)	0.69 (0.58–0.81)
No	871	1.00	1.00	1.00	1.00
Examination period
Nov. 1-Apr. 31	857	1.00	1.00	1.00	1.00
May 1-Oct. 31	957	0.37 (0.23–0.60)	0.51 (0.37–0.71)	0.52 (0.40–0.68)	0.58 (0.47–0.73)
Body mass index (kg/m2)**
<25.0	785	1.00	1.00	1.00	1.00
25.0–29.9	455	1.32 (0.93–1.86)	1.06 (0.77–1.46)	1.48 (1.13–1.93)	1.25 (0.97–1.60)
≥30.0	574	3.37 (2.41–4.72)	1.74 (1.27–2.38)	2.11 (1.58–2.81)	1.94 (1.54–2.45)
Chronic condition
Hypertension
Yes	120	2.44 (1.72–3.46)	0.95 (0.67–1.34)	1.39 (0.99–1.96)	0.92 (0.64–1.31)
No	1,694	1.00	1.00	1.00	1.00
Diabetes
Yes	44	2.06 (1.13–3.74)	1.52 (1.01–2.32)	1.59 (1.08–2.34)	1.02 (0.68–1.54)
No	1,770	1.00	1.00	1.00	1.00
Cardiovascular disease
Yes	32	3.12 (1.90–5.14)	2.30 (1.31–4.04)	1.51 (0.97–2.33)	1.50 (0.96–2.34)
No	1,782	1.00	1.00	1.00	1.00
Asthma
Yes	171	1.35 (0.94–1.92)	1.00 (0.73–1.37)	0.86 (0.59–1.26)	0.89 (0.67–1.19)
No	1,643	1.00	1.00	1.00	1.00
Lifestyle-related behavior
Current Smoking
Yes	385	1.25 (0.85–1.85)	1.40 (1.06–1.85)	1.06 (0.86–1.31)	1.08 (0.89–1.31)
No	1,429	1.00	1.00	1.00	1.00
Physical activity
Yes	1,558	0.39 (0.28–0.54)	0.87 (0.61–1.24)	0.77 (0.60–0.99)	1.19 (0.92–1.54)
No	256	1.00	1.00	1.00	1.00
Any alcohol use
Yes	1,203	0.52 (0.39–0.71)	0.82 (0.61–1.09)	0.69 (0.56–0.84)	0.90 (0.75–1.07)
No	611	1.00	1.00	1.00	1.00
Healthcare access
Insurance coverage
Yes	1,388	0.59 (0.41–0.84)	1.01 (0.70–1.46)	0.65 (0.52–0.80)	0.94 (0.77–1.15)
No	426	1.00	1.00	1.00	1.00
Healthcare visit
Yes	1,609	0.61 (0.42–0.87)	0.87 (0.64–1.19)	0.70 (0.54–0.90)	0.84 (0.64–1.09)
No	205	1.00	1.00	1.00	1.00

*Prevalence ratios and 95% confidence intervals were estimated using log-linear regression models without and with adjustment for all other variables listed in the table; women with serum 25(OH)D ≥20 ng/mL was used as the referent.
**Self-reported prepregnant weight and height were used to calculate body mass index (BMI) for pregnant women, and measured weight and height were used to calculate BMI for nonpregnant women.