Table 4.

Subgroup analysis of multivariable-adjusted associations of serum Mg and radiographic knee OA (n = 2855). Values are adjusted OR (95% CI) unless otherwise indicated.

Variables	Median Mg Level, mmol/l	Quartiles of Serum Mg				p for Trends
Variables	Median Mg Level, mmol/l	Q1, Lowest	Q2	Q3	Q4, Highest	p for Trends
BMI
< 30 kg/m²	0.91	1.00, reference	0.82 (0.65–1.04)	0.88 (0.70–1.12)	0.72 (0.57–0.92)^*	0.01
≥ 30 kg/m²	0.91	1.00, reference	4.72 (1.55–14.54)^*	2.48 (0.79–7.81)	0.80 (0.23–2.82)	0.82
Alcohol drinking status
Yes	0.91	1.00, reference	1.32 (0.90–1.94)	1.24 (0.86–1.81)	0.90 (0.61–1.33)	0.60
No	0.91	1.00, reference	0.72 (0.54–0.96)^*	0.75 (0.56–1.01)	0.63 (0.47–0.86)^*	0.00

↵* p < 0.05, relative to the lowest serum category. Mg: magnesium; OA: osteoarthritis; BMI: body mass index.