Table 2.

Covariates adjusted for models of the associations between metabolic syndrome and osteoporosis.

Authors, year	Covariates
Kim et al. 2013 [18]	Men and premenopausal women adjusted for age, BMI, WBC count, alkaline phosphatase, smoking, alcohol intake, PHA, self-reported health status, daily calcium intake, chronic disease, rheumatoid arthritis, cancer, and parental osteoporosis; postmenopausal women further adjusted for years since menopause and postmenopausal hormone therapy
Maghraoui et al. 2014 [19]	Age, BMI, years since menopause, and number of pregnancies
Lee et al. 2015 [20]	Age, calcium intake, serum 25-OH vitamin D level, serum parathyroid hormone level, smoking status, alcohol consumption, PHA, hormone replacement therapy (in women), and muscle mass
Eckstein et al. 2016 [21]	None
Abbasi et al. 2017 [22]	None
Heidari et al. 2017 [23]	Age, BMI, muscle strength, PHA, educational level, history of fractures, abdominal obesity, smoking, and other biochemical parameters
Chen et al. 2018 [15]	Age, serum total cholesterol, alkaline phosphatase, and nonalcoholic fatty liver disease
Loke et al. 2018 [13]	None
Lin et al. 2018 [14]	Age, aspartate aminotransferase, creatinine, hemoglobin, and exercise status

Note. BMI, body mass index; WBC, white blood cell; PHA, physical activities.