TABLE 4.

Results of subgroup analyses of the comparison of relative telomere length (rTLT) in obese vs. non-obese individuals according to the study or participants “characteristics”.

Group	No. of studies	WMD (95% CI)	P	Pheterogeneity	I2, %	Pbetween study heterogeneity
Total*	12	−0.036 −0.05, −0.02	<0.001	< 0.001	100
Weight status						< 0.001
Obese	8	−0.042 −0.07, −0.014	0.003	< 0.001	99
Overweight	4	−0.025 −0.058, 0.008	0.145	< 0.001	100
Continent						< 0.001
United States	7	−0.019 −0.044, 0.005	0.127	< 0.001	100
Europe	4	−0.076 −0.144, −0.007	0.03	< 0.001	94.5
Asia/Australia	1	−0.013 −0.016, −0.010	< 0.001	−	−
Sample size						< 0.001
≤ 1,000	2	−0.115 −0.223 −0.007	0.037	< 0.001	96.9
1,000–5,000	6	−0.025 −0.031 −0.019	<0.001	< 0.001	96.8
> 5,000	4	−0.020 −0.057 0.017	0.293	< 0.001	100
Gender						< 0.001
Both	9	−0.022 −0.044 0.000	0.052	< 0.001	100
Men or women	3	−0.080 −0.173 0.013	0.090	< 0.001	98.6
Quality score						< 0.001
6 ≥	3	−0.041 −0.060 −0.022	<0.001	< 0.001	99.8
8	2	−0.030 −0.031 −0.029	< 0.001	1	0
9	7	−0.017 −0.027 −0.007	0.001	< 0.001	98.9
Age range						< 0.001
> 18–20	6	−0.023 −0.049 0.002	0.071	< 0.001	100
40–75	4	−0.063 −0.143 0.016	0.118	< 0.001	97.7
> 75	2	−0.008 −0.125 0.108	0.889	0.014	83.5

*Note that because all of included studies had cross-sectional designs, they were performed in healthy individuals, and the relative telomere length measurement method was quantitative polymerase chain reaction (qPCR); therefore, subgrouping according to these parameters was not performed.