Obstructive sleep apnea and bone mineral density in obese patients

Figures & data

Table 1 Descriptive characteristics of subjects with varying severities of obstructive sleep apnea (OSA)

	Total	Mild OSA (AHI 5–14/h)	Moderate OSA (AHI 15–29/h)	Severe OSA (AHI ≥ 30/h)
Number	115	50	33	32
Male/female	56/59	16/34	19/14	21/11
Age (yr)	56.00 (47.25–61.75)	55.00 (44.5–58.75)	56.00 (49.75–62.0)	57.00 (50.0–63.0)
AHI (events/h)	17.00 (8.5–30.75)	8.0 (6.0–10.12)	22.5 (17.4–25.9)a	45.9 (39.7–63.92)a,b
Height (cm)	168.0 (161.0–173.0)	167.5 (158.0–171.2)	168.0 (161.0–174.5)	168.0 (165.0–174.0)
Body weight (kg)	101.1 (90.0–111.9)	97.25 (87.75–112.8)	100.0 (89.5–109.8)	104.5 (97.25–119.25)
BMI (kg/m^2)	35.41 (32.16–39.72)	36.10 (31.67–40.55)	34.78 (31.75–38.07)	36.86 (33.44–49.9)
Lean mass (kg)	57.7 (51.31–65.53)	54.8 (48.82–59.48)	59.23 (51.77–67.82)	64.52 (55.69–69.54)a
Metabolic syndrome lndicators
WC (cm)	106.5 (101.3–123.0)	106.7 (99.5–117.25)	104.3 (101.2–119.0)	108.7 (102.9–128.5)
FPG (mg/dL)	98.0 (90.0–105.0)	96.5 (89.0–102.2)	98.0 (91.0–108.5)	100.0 (89.25–112.2)
Systolic BP (mmHg)	140.0 (130.0–145.0)	132.5 (120.0–140.5)	140.0 (129.0–143.5)	140.0 (130.0–150.0)
Diastolic BP (mmHg)	90.0 (80.0–90.0)	85.5 (80.0–90.0)	90.0 (80.0–90.0)	90.0 (81.25–95.0)
HDL-C (mg/100 mL)	44.3 (37.77–52.0)	49.0 (41.75–55.1)	43.00 (36.0–51.0)	39.15 (35.0–49.25)a
Triglycerides (mg/dL)	140.0 (110.25–168.75)	138.6 (107.8–167.2)	130.0 (107.5–175.0)	151.5 (117.5–174.0)
Inflammatory indicators
ESR (mm/h)	22.0 (13.25–29.0)	18.5 (11.5–30.5)	18.0 (14.5–27.0)	26.0 (22.0–29.75)
CRP (mg/dL)	0.8 (0.6–1.1)	0.97 (0.57–1.39)	0.7 (0.5–0.85)a	0.9 (0.8–0.99)
Fibrinogen (mg/dL)	378.0 (350.2–415.75)	370.0 (329.7–413.2)	360.0 (335.0–375.0)	404.0 (390.0–424.2)a,b
BMD indicators
L1–L4 (g/cm^2)	1.05 (0.94–1.11)	1.05 (0.93–1.12)	1.01 (0.89–1.08)	1.06 (1.04–1.14)
Total hip (g/cm^2)	1.02 (0.93–1.11)	1.01 (0.93–1.11)	0.99 (0.92–1.05)	1.05 (0.96–1.15)
Femoral neck (g/cm^2)	0.83 (0.75–0.96)	0.88 (0.74–0.97)	0.79 (0.74–0.91)	0.79 (0.77–0.96)
Osteopenia, n° and (%)	46 (44.35%)	15 (30%)	17 (51.52%)	14 (43.75%)
Osteoporosis, n° and (%)	5 (%)	3 (6%)	0 (0%)	2 (6.25%)
BMD of women in pre-menopause and menopause
Menopause
L2–L4 BMD (g/cm^2)	0.971 (0.89–1.07)	0.97 (0.81–1.2)	0.92 (0.86–1.0)	1.05 (0.84–1.11)
Hip BMD (g/cm^2)	0.956 (0.859–1.082)	0.98 (0.83–1.09)	0.93 (0.86–0.96)	1.1 (0.92–1.15)
Femoral neck BMD (g/cm^2)	0.77 (0.639–0.907)	0.82 (0.63–0.94)	0.69 (0.64–0.77)	0.88 (0.71–1.1)
Pre-menopause
L2–L4 BMD (g/cm^2)	1.09 (1.05–1.11)	1.1 (1.04–1.12)	1.08 (0.96–1.3)	1.06 (0.98–1.09)
Hip BMD (g/cm^2)	1.031 (0.95–1.10)	1.02 (0.99–1.1)	1.03 (0.92–1.26)	1.06 (0.86–1.12)
Femoral neck BMD (g/cm^2)	0.88 (0.80–0.95)	0.90 (0.81–0.95)	0.92 (0.83–1.1)	0.80 (0.72–0.85)

Notes: Values are expressed as median values, 25th–75th percentiles;

a significantly different from mild OSA group (P < 0.05);

b significantly different from moderate OSA group (P < 0.05).

Abbreviations: AHI, apnea-hypopnea index; BMI, body mass index; WC, waist circumference; FPG, fasting plasma glucose; BP, blood pressure; HDL-C, high density lipoprotein-cholesterol; MetS, metabolic syndrome; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; BMD, bone mineral density; OSA, obstructive sleep apnea.

Table 2 Spearman’s correlation coefficient analysis for all the covariates

	AHI	Age	Weight	BMI	WC	FPG	SBP	DBP	HDL-C	TG	CRP	ESR	Fibrinogen	Lean mass
AHI														0.32‡
Age	0.2†													−0.19†
Weight	0.10	−0.40‡												0.58‡
BMI	−0.01	−0.23†	0.72‡											0.16
WC	0.09	−0.24†	0.73‡	0.73‡										0.32‡
FPG	0.11	0.21†	0.22†	0.22†	0.21†									0.05
Systolic BP	0.19†	0.34‡	0.00	0.02	0.13	0.25†								0.07
Diastolic BP	0.21†	0.30‡	−0.03	−0.02	0.09	0.07	0.78‡							0.03
HDL-C	−0.23†	−0.08	−0.14	0.05	−0.00	−0.03	−0.26†	−0.19†						−0.35‡
TG	0.02	0.20†	0.01	0.08	0.05	0.25†	0.26†	0.16	−0.24†					0.09
CRP	−0.01	0.05	0.12	0.18†	0.16	0.06	0.03	−0.01	−0.07	0.14				0.03
ESR	0.19†	−0.05	0.28†	0.29†	0.35‡	0.12	0.12	0.19†	−0.18	0.15	0.43‡			0.16
Fibrinogen	0.27†	−0.07	0.20†	0.16	0.19†	0.02	0.04	0.11	−0.17	0.03	0.50‡	0.48‡		0.20†
L1–L4 BMD	0.00	−0.31‡	0.34‡	0.28†	0.14	−0.04	−0.20†	−0.20†	−0.02	−0.08	−0.04	0.13	0.11	0.18†
Hip BMD	0.06	−0.30‡	0.32‡	0.17	0.24†	0.03	0.03	−0.02	−0.18	−0.04	−0.02	0.17	0.16	0.24†
FN BMD	−0.11	−0.35‡	0.28†	0.18	0.15	−0.01	−0.04	−0.12	−0.07	−0.10	0.05	0.14	0.08	0.16

Notes:

† P < 0.05;

‡ P < 0.001.

Abbreviations: AHI, apnea-hypopnea index; BMI, body mass index; WC, waist circumference; FPG, fasting plasma glucose; DBP, diastolic blood pressure; HDL-C, high density lipoprotein-cholesterol; TG, triglycerides; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FN, femoral neck; BMD, bone mineral density; SBP, systolic blood pressure.