Prevalence and Associated Factors of Vitamin D Deficiency in High Altitude Region in Saudi Arabia: Three-Year Retrospective Study

Figures & data

Table 1 Baseline Characteristics and Patients Demographics

		Study Group (N= 2153)	No Vitamin D Deficiency	Vitamin D Deficiency	p-value*
Age		43.5 ± 15.9	46.4 ± 15.8	39.6 ± 15.4	<0.001
<25 years old		196 (9.1%)	69 (5.5%)	127 (14.1%)
25–39 years old		767 (35.6%)	388 (31%)	378 (42%)
40–59 years old		817 (37.9%)	526 (42%)	290 (32.2%)
≥60 years old		373 (17.3%)	268 (21.4%)	105 (11.7%)
Gender	Female	1382 (64.0%)	66.2%	61.3%	0.021
	Male	771 (35.7%)	33.8%	38.7%
Nationality	Saudi	1997 (92.8%)	93.0%	92.3%	0.730
	Yemeni	51 (2.4%)	2.2%	2.7%
	Egyptian	42 (2%)	1.8%	2.2%
	Others	63 (2.9%)	3.0%	2.8%
Hypertension		370 (17.2%)	20.5%	12.6%	<0.001
Diabetes Mellitus		352 (16.3%)	19.2%	12.4%	<0.001
Heart Disease		51 (2.4%)	2.9%	1.7%	0.069
Asthma		60 (2.8%)	3.6%	1.7%	0.007
Thyroid disease		384 (17.8%)	21.5%	12.8%	<0.001
Osteoporosis		33 (1.5%)	1.9%	1.0%	0.087
Gout		39 (1.8%)	2.0%	1.6%	0.448
eGFR Category	eGFR≥ 90	557 (79.3%)	79.1%	79.8%	0.818
	eGFR (60–90)	105 (15.0%)	15.5%	14.1%
	eGFR< 60	40 (5.7%)	5.4%	6.1%
Specialty of referring physician	Internal Medicine	1313 (61%)	62.3%	59.1%	0.117
	Neurology	248 (11.5%)	10.8%	12.6%
	Rheumatology	166 (7.7%)	8.1%	7.2%
	Orthopedic surgery	163 (7.6%)	8.1%	6.9%
	Obstetric/Gyncology	93 (4.3%)	3.8%	5.1%
	Others	170 (7.9%)	7.0%	9.1%
Reason for vitamin D request	Screening	2084 (96.8%)	96.4%	97.3%	0.227
	Clinical indication	69 (3.2%)	3.6%	2.7%

Notes: *P-value between patients with vitamin D deficiency (<20 ng/mL) and the rest of the patients. Data are expressed as mean ± SD or number (%). Other nationalities included Syrian, Afghan, Sudanese, Somali, Pakistani, and Indian patients. Heart Diseases include arrhythmia, ischemic heart disease, hypertensive heart disease, and dilated cardiomyopathy. Thyroid diseases include hypo- and hyperthyroidism and goiter. The clinical indications for vitamin D include myalgia, bone pain, and anxiety. Bold P values <0.05.

Figure 1 Vitamin D deficiency categorized according to age groups and gender.

Table 2 Laboratory Results Among Study Group and According to 25 (OH) Vitamin D Status

		Study Group	No Vitamin D Deficiency	Vitamin D Deficiency	p-value*
CBC	25 (OH) vitamin D level (ng/mL)	22.0 (15.0–31.8)	29.8 (24.2–38.8)	14.0 (11.2–16.9)	<0.001
	WBCs (*10^9/L)	7.21 (5.84–8.68)	7.29 (5.92–8.64)	7.05 (5.68–8.75)	0.321
	Neutrophils (%)	51.4 (42.7–58.4)	51.4 (42.5–58.4)	51.4 (43.7–58.4)	0.861
	Lymphocytes (%)	37.3 (31.5–44.9)	37.2 (31.1–44.9)	37.3 (31.8–44.9)	0.325
	Monocytes (%)	7.30 (6.10–8.80)	7.30 (6.10–8.70)	7.30 (6.10–8.90)	0.537
	Eosinophils (%)	2.00 (1.30–3.20)	2.10 (1.37–3.48)	1.90 (1.20–3.00)	0.002
	Basophils (%)	0.40 (0.20–1.09)	0.40 (0.20–1.11)	0.40 (0.20–1.01)	0.200
	RBCs (*10^12/L)	5.02 (4.65–5.45)	5.03 (4.66–5.47)	5.00 (4.65–5.45)	0.648
	Hemoglobin (g/dL)	13.9 (12.8–15.2)	14.0 (12.9–15.2)	13.8 (12.7–15.1)	0.098
	HCT (%)	42.0 (38.8–45.5)	42.1 (39.0–45.7)	41.7 (38.5–45.3)	0.170
	MCV (fL)	84.4 (80.6–87.7)	84.7 (81.1–88.4)	83.6 (80.1–87.0)	<0.001
	MCH (pg)	28.2 (26.3–29.5)	28.4 (26.5–29.6)	27.9 (26.1–29.3)	0.001
	MCHC (g/dL)	33.3 (31.8–34.4)	33.3 (31.8–34.5)	33.3 (31.8–34.3)	0.467
	RDW (%)	13.0 (12.0–14.1)	13.0 (11.9–14.1)	13.0 (12.1–14.0)	0.295
	Platelets (*10^9/L)	270 (229–320)	268 (227–313)	272 (231–325)	0.130
Thyroid Profile	TSH (mIU/L)	1.69 (1.09–2.57)	1.78 (1.07–2.75)	1.62 (1.09–2.38)	0.227
	Free T3 (pmol/L)	3.12 (2.53–3.91)	3.04 (2.52–3.85)	3.46 (2.53–4.25)	0.026
	Free T4 (pmol/L)	11.9 (10.7–13.2)	11.8 (10.6–13.1)	11.97 (11.1–13.2)	0.371
Lipid profile	Triglycerides (mmol/L)	1.43 (1.02–2.00)	1.43 (1.03–1.98)	1.39 (0.97–2.06)	0.633
	Cholesterol (mmol/L)	4.82 (4.19–5.64)	4.97 (4.25–5.68)	4.67 (4.01–5.61)	0.062
	HDL (mmol/L)	1.17 (1.00–1.37)	1.19 (1.04–1.41)	1.14 (0.96–1.34)	0.017
	LDL (mmol/L)	3.53 (2.92–4.21)	3.55 (2.94–4.22)	3.44 (2.90–4.14)	0.300
Liver Function	SGPT (U/L)	21.0 (15.0–30.0)	20.0 (15.0–27.1)	22.0 (15.0–34.0)	0.042
	SGOT (U/L)	19.0 (16.0–24.0)	19.0 (16.0–24.0)	20.0 (17.0–24.0)	0.099
	Total Bilirubin (µmol/L)	10.1 (6.85–14.0)	9.70 (6.55–13.95)	10.45 (7.68–14.08)	0.115
	Direct Bilirubin (µmol/L)	3.50 (2.50–4.85)	3.40 (2.50–4.60)	3.70 (2.60–5.13)	0.045
	GGT (U/L)	20.0 (12.0–35.5)	20.0 (12.0–33.0)	20.5 (12.3–37.0)	0.887
	Alkaline phosphatase (IU/L)	64.0 (53.0–80.0)	65.0 (53.0–80.0)	63.0 (53.0–81.5)	0.807
	Total protein (g/L)	73.0 (69.0–77.0)	72.0 (69.0–76.0)	73.0 (69.0–77.0)	0.437
	Albumin (g/L)	44.0 (41.0–46.0)	43.0 (41.0–46.0)	44.0 (42.0–46.0)	0.061
	HemoglubinA1c (%)	6.00 (5.30–7.70)	6.00 (5.40–7.70)	6.00 (5.20–7.70)	0.235
	ESR (mm/hr)	17.0 (10.0–23.0)	17.0 (13.0–23.0)	16.0 (8.0–22.5)	0.142
	C-Reactive Protein (mg/L)	3.04 (1.18–9.33)	3.18 (1.32–10.67)	2.58 (0.78–8.64)	0.120
	Serum Creatinine (µmol/L)	64.0 (56.5–75.0)	63.6 (56.3–74.0)	64.7 (56.9–79.0)	0.102
	eGFR (mL/min/1.73m^2)	109 (93.9–120)	105 (93.3–116)	109 (93.9–120)	0.206
	Serum Uric acid (mg/dL)	5.30 (4.15–6.50)	5.30 (4.16–6.34)	5.30 (4.11–6.75)	0.528
	Serum Calcium (mmol/L)	2.32 (2.25–2.41)	2.32 (2.26–2.41)	2.33 (2.24–2.40)	0.500
	Vitamin B12 level (pg/mL)	289 (205–434)	308 (217–504)	285 (191–372)	0.015

Notes: *P-value between patients with vitamin D deficiency (<20 ng/mL) and the rest of the patients. Data are expressed as the median (interquartile range). Bold P values <0.05.

Abbreviations: RDW, red cell distribution width; HCT, Hematocrit, MCV, Mean corpuscular volume; MCH, Mean corpuscular hemoglobin; MCHC, Mean corpuscular hemoglobin concentration; ESR, Erythrocyte sedimentation rate; HDL, high-density lipoprotein; LDL, low-density lipoprotein; SGPT, Serum glutamic pyruvic transaminase; SGOT, Serum glutamic-oxaloacetic transaminase; GGT, Gamma-glutamyl transferase.

Table 3 Significant Correlations Between Vitamin-D Level and Other Parameters

	25 (OH) Vitamin D Level
	Rho	p-value
Age	0.216	<0.001
MCV	0.071	0.006
MCH	0.069	0.007
Monocytes	−0.053	0.041
Eosinophils	0.088	<0.001
Cholesterol	0.099	0.008
HDL	0.117	0.002
SGOT	−0.087	0.034
Serum Calcium	0.085	0.043
Vitamin B12 level	0.199	<0.001

Abbreviations: MCV, mean corpuscular volume; MCH, Mean corpuscular hemoglobin; HDL, high-density lipoprotein; SGOT, Serum glutamic-oxaloacetic transaminase.

Table 4 Binary Logistic Regression for Predictors of Vitamin D Deficiency Among Patients’ Characteristic

	B	S.E.	Wald	Sig.	AOR	95% C.I for AOR
						Lower	Upper
Age	−0.027	0.003	62.57	<0.001	0.973	0.967	0.980
Thyroid Disease (Yes)	−0.537	0.125	18.35	<0.001	0.585	0.457	0.747
Asthma (Yes)	−0.621	0.311	3.981	0.046	0.537	0.292	0.989
Sex (Male)	0.165	0.095	3.057	0.080	1.180	0.980	1.420
Hypertension (Yes)	−0.007	0.152	0.002	0.963	0.993	0.737	1.338
Diabetes millets (Yes)	−0.018	0.152	0.014	0.907	0.982	0.730	1.322

Note: Bold P values <0.05.

Abbreviations: AOR, adjusted odds ratio; CI, confidence interval.

Table 5 Binary Logistic Regression for Predictors of Vitamin D Deficiency Among Patients’ Laboratory Data

	B	S.E.	Wald	Sig.	AOR	95% C.I for AOR
						Lower	Upper
MCV (fL)	−0.117	0.077	2.298	0.130	0.889	0.764	1.035
Eosinophils (%)	−0.625	0.369	2.878	0.090	0.535	0.260	1.102
HDL	−0.779	1.462	0.284	0.594	0.459	0.026	8.059
SGOT	−0.030	0.042	0.489	0.484	0.971	0.893	1.055
Vitamin B level (pg/mL)	−0.001	0.003	0.290	0.590	0.999	0.993	1.004
Serum Calcium (mg/dl)	2.915	1.338	4.748	0.029	18.46	1.340	254.1

Note: Bold P values <0.05.

Abbreviations: AOR, adjusted odds ratio; CI, Confidence interval; MCV, mean corpuscular volume; HDL, high-density lipoprotein; SGOT, Serum glutamic-oxaloacetic transaminase.

Table 6 Binary Logistic Regression for Significant Predictors of Vitamin D Deficiency

	B	S.E.	Wald	Sig.	Exp (B)	95% C.I for EXP (B)
						Lower	Upper
Age (years)	−0.022	0.005	16.24	<0.001	0.978	0.968	0.989
Thyroid Disease (Yes)	−0.559	0.222	6.342	0.012	0.572	0.370	0.883
Asthma (Yes)	−2.282	1.050	4.720	0.030	0.102	0.013	0.800

Note: Bold P values <0.05.