Table 5.

Studies reporting an association between vitamin D status, insulin resistance, and beta cell function in non-diabetic subjects

Study (country of origin)	Gender (M/F)	Outcomes	Adjustments	Main study results
Ding et al., 2014(11) (China)	M/F (n = 897)	Lg (HOMA-IR)	age, gender, BMI	25(OH)D inversely associated with Lg (HOMA-IR) (p<0.001)
Tao et al., 2013(14) (China)	F (n = 1,382)	HOMA-IR, HOMA-B	age, PTH, Ca2+, BMI	25(OH)D inversely associated with HOMA-IR (p<0.001) and HOMA-B (p = 0.001)
Del Gobbo et al., 2011(19) (Canada)	M/F (n = 510)	HOMA-IR, HOMA-B	age, gender, physical activity, smoking, alcohol, education, BMI, WC, body fat percentage	25(OH)D not associated with HOMA-IR (p = 0.572) and HOMA-B (p = 0.498)
Zhao et al., 2010(25) (USA)	M/F (n = 3,206)	HOMA-IR	age, gender, race/ethnicity, education, smoking, heavy alcohol, drinking, physical activity, abdominal obesity, BMI	25(OH)D inversely associated with HOMA-IR (ptrend<0.001)
Liu et al., 2009(26) (USA)	M/F (n = 2,803)	HOMA-IR, ISI0,120	age, gender, current smoking status, BMI, WC	25(OH)D inversely associated with HOMA-IR (p<0.001), but not associated with ISI0,120 (p = 0.310)
Hao et al., 2014(27) (China)	M (n = 567)	HOMA-IR	age, BMI	25(OH)D not associated with HOMA-IR (p = 0.558)