TABLE 3.

Meta-analysis showing the effect of zinc supplementation on BMI (in kg/m²) based on several subgroups¹

		Meta-analysis			Heterogeneity
Study group	Studies, n	Participants, n	WMD (95% CI), kg/m2	P-effect	Q statistic	P-within group	I 2 (%)	P-between group
Overall	21	1230	0.00 (−0.17, 0.18)	0.97	46.37	0.001	56.9	—
Sex								<0.001
Female	6	296	0.04 (−0.25, 0.35)	0.76	14.62	0.01	65.8
Both	15	934	−0.02 (−0.20, 0.16)	0.82	18.68	0.17	25.1
Type of zinc supplement								0.03
Sulfate	13	723	0.06 (−0.17, 0.30)	0.59	36.07	<0.001	66.7
Gluconate	5	259	−0.10 (−0.40, 0.19)	0.47	1.66	0.79	0.0
Aminochelate	2	110	−0.08 (−0.50, 0.33)	0.68	0.01	0.90	0.0
Elemental	1	138	−0.10 (−0.55, 0.35)	0.66	0.00	—	—
Zinc supplemented, mg/d								0.001
<40	12	741	−0.07 (−0.26, 0.10)	0.41	3.69	0.97	0.0
≥40	9	489	0.07 (−0.21, 0.36)	0.62	32.04	<0.001	75.0
Baseline BMI, kg/m2								0.02
Nonoverweight (≤24.9)	5	330	−0.005 (−0.36, 0.35)	0.97	8.65	0.07	53.7
Overweight and obese (≥25)	16	900	0.009 (−0.19, 0.20)	0.93	32.47	0.006	53.8
Study duration, wk								0.009
Short period (≤8)	12	613	0.007 (−0.25, 0.27)	0.96	37.39	<0.001	70.6
Long period (>8)	9	617	−0.03 (−0.22, 0.16)	0.74	2.20	0.97	0.0
Study design								0.001
Parallel	20	1165	0.04 (−0.12, 0.21)	0.59	35.42	0.01	46.4
Crossover	1	65	−0.35 (−0.68, −0.17)	0.04	0.00	—	—
Health status of subjects								<0.001
Healthy overweight/obese	4	227	−0.17 (−0.47, 0.13)	0.26	0.90	0.82	0.0
Insulin resistance–related disorders2	7	438	−0.03 (−0.22, 0.15)	0.68	5.49	0.48	0.0
Hemodialysis	4	219	0.16 (−0.40, 0.72)	0.57	10.94	0.01	72.6
Cardiovascular events	2	80	0.03 (−0.57, 0.63)	0.91	0.05	0.82	0.0
Hypothyroidism	1	28	−0.12 (−0.98, 0.74)	0.78	0.00	—	—
Depression	1	38	−0.50 (−1.83, 0.83)	0.46	0.00	—	—
Osteoporosis	1	60	0.40 (0.28, 0.51)	<0.001	0.00	—	—
Pulmonary tuberculosis	1	140	−0.10 (−0.55, 0.35)	0.66	0.00	—	—

¹All analyses were conducted using a random-effects model. WMD, weighted mean difference.

²Including polycystic ovarian syndrome, type 2 diabetes mellitus, and prediabetes.