Association of Single Nucleotide Polymorphisms in Estrogen Receptor Alpha Gene with Susceptibility to Knee Osteoarthritis: A Case-Control Study in a Chinese Han Population

Table 1

Baseline characteristics of subjects.

	Cases	Controls	𝑃 value
Subjects, number	469	522	—
Females, number (%)	356 (75.9)	120 (23.0)	𝑃<0.001^∗
Mean age, y (SD)	57.3±10.9	56.4±9.8	𝑃=0.473
Mean BMI, kg/m^2(SD)	26.1±3.9	24.3±2.8	𝑃<0.001
Kellgren-Lawrence grading
Grade 2, number (%)	255 (54.5)	0 (0.0)	—
Grade 3, number (%)	119 (25.3)	0 (0.0)	—
Grade 4, number (%)	95 (20.2)	0 (0.0)	—

No.: number; y: years; SD: standard deviation.
∗Pearson chi-square test.