Table 4.

Mean bone mineral density according to lifestyle factors and vitamin D receptor gene polymorphism

Characteristic	All (n = 524)		TT (n = 426)		Tt + tt (n = 98)
	n (%)	BMD (mean ± SD)	n (%)	BMD (mean ± SD)	n (%)	BMD (mean ± SD)
Past history of exercise
No	104 (19.9)	0.54 ± 0.06	82 (19.3)	0.54 ± 0.06	22 (22.7)	0.53 ± 0.06
Yes	418 (80.1)	0.56 ± 0.06a	343 (80.7)	0.57 ± 0.06b	75 (77.3)	0.56 ± 0.05c
Current exercise
No	278 (54.2)	0.55 ± 0.06	220 (52.8)	0.55 ± 0.06	58 (60.4)	0.55 ± 0.05
1–2 days/week	180 (35.1)	0.56 ± 0.06	149 (35.7)	0.56 ± 0.06	31 (32.3)	0.56 ± 0.06
3–7 days/week	55 (10.7)	0.58 ± 0.06a	48 (11.5)	0.58 ± 0.05b	7 (7.3)	0.55 ± 0.07
Number of meals daily
3 meals/day	427 (81.5)	0.56 ± 0.06	347 (81.5)	0.56 ± 0.06	80 (81.6)	0.56 ± 0.06
2 meals/day	97 (18.5)	0.55 ± 0.06	79 (18.5)	0.56 ± 0.06	18 (18.4)	0.51 ± 0.04d,e
Smoking status
No	200 (38.7)	0.56 ± 0.06	160 (38.1)	0.56 ± 0.06	40 (41.2)	0.55 ± 0.05
1–20 cigarettes/day	254 (49.1)	0.56 ± 0.06	204 (48.6)	0.56 ± 0.06	50 (51.6)	0.55 ± 0.06
≥21 cigarettes/day	63 (12.2)	0.56 ± 0.06	56 (13.3)	0.57 ± 0.06	7 (7.2)	0.51 ± 0.05f
Alcohol intake
No	155 (30.4)	0.55 ± 0.06	129 (31.3)	0.55 ± 0.06	26 (26.5)	0.55 ± 0.06
Sometimes	141 (27.6)	0.55 ± 0.06	116 (28.2)	0.56 ± 0.06	25 (25.5)	0.54 ± 0.06
Every day	214 (42.0)	0.57 ± 0.06a	167 (40.5)	0.57 ± 0.06	47 (48.0)	0.56 ± 0.05

Data are mean ± SD

BMD bone mineral density

BMD was adjusted for age and BMI by analysis of covariance (ANCOVA)

^aP < 0.05 compared with “No” in all subjects

^bP < 0.05 compared with “No” in TT subjects

^cP < 0.05 compared with “No” in Tt plus tt subjects

^dP < 0.05 compared with 2 meals/day in TT subjects

^eP < 0.05 compared with 3 meals/day in Tt plus tt subjects

^fP < 0.05 compared with ≥21 cigarettes/day in TT subjects