Body mass index increases the lymph node metastasis risk of breast cancer: a dose-response meta-analysis with 52904 subjects from 20 cohort studies

Table 2 Subgroup analyses showing difference between studies included in the meta-analysis (highest versus lowest BMI)

Variables	Number of studies	Number of cases	Pooled RR (95%CI)	Test of heterogeneity		Publication bias
Variables	Number of studies	Number of cases	Pooled RR (95%CI)	I²(%)	P value	Begg's P value	Egger's P value
All	20	30938	1.10 (1.06, 1.15)	43.0	0.022	0.538	0.003
Area
Asia	3	2968	1.18 (1.08, 1.30)	0.0	0.555	1.000	0.339
Europe	8	19791	1.08 (1.05, 1.12)	44.6	0.082	0.266	0.116
America	8	3847	1.13 (1.04, 1.23)	47.4	0.065	0.902	0.079
Menopausal
Pre	5	4291	1.12 (1.04, 1.20)	31.6	0.211	0.806	0.489
Post	6	4479	1.28 (1.14, 1.44)	0.0	0.865	0.452	0.656
Study period
≤ 5y	6	2250	1.31 (1.14, 1.50)	0.0	0.709	0.707	0.860
> 5y	14	28688	1.07 (1.05, 1.10)	26.8	0.167	0.743	0.051
Study population
TNBC	2	429	1.15 (0.88, 1.49)	0.0	0.789	1.000	---
Non-TNBC	18	30539	1.08 (1.06, 1.11)	48.2	0.012	0.363	0.003

ISSN: 1471-2407