Allergic conditions are not associated with the risk of non-Hodgkin’s lymphoma or Hodgkin’s lymphoma: a systematic review and meta-analysis

Figures & data

Figure 1 Flow diagram of the selection process.

Note: Several studies assessed the risk of both NHL and HL.
Abbreviations: NHL, non-Hodgkin lymphoma; HL, Hodgkin lymphoma.

Figure 2 Association between history of allergic conditions and the risk of NHL.

Notes: (A) Pooled analysis of case–control studies. (B) Pooled analysis of cohort studies. Weights are from random-effects analysis.
Abbreviations: CI, confidence interval; NHL, non-Hodgkin’s lymphoma; OR, odds ratio.

Table 1 Association between history of allergic conditions and the risk of NHL/HL according to study design

Factor	Number of studies	Pooled OR/RR (95% CI)	Heterogeneity
			I^2 (%)	P-value
NHL
All case–control study	24	0.83 (0.76–0.91)	66.7	<0.001
Population based	15	0.80 (0.73–0.88)	63.8	<0.001
Hospital based	9	0.90 (0.71–1.13)	67.1	0.002
All cohort study	13	1.18 (0.98–1.42)	88.7	<0.001
Prospective	9	1.05 (0.86–1.28)	81.3	<0.001
Retrospective	4	1.54 (0.91–2.58)	95.0	<0.001
All case–control and cohort studies	37	0.93 (0.84–1.04)	87.8	<0.001
HL
All case–control study	10	0.96 (0.84–1.09)	19.4	0.265
Population based	7	1.00 (0.86–1.15)	34.6	0.164
Hospital based	3	0.79 (0.58–1.08)	0	0.893
All cohort study	2	1.46 (0.63–3.38)	58.3	0.121
All case–control and cohort studies	12	0.99 (0.88–1.11)	26.5	0.184

Note: The OR/RR of individual study was pooled with a random-effects model if there was significant heterogeneity, otherwise a fixed-effects model was used.

Abbreviations: CI, confidence interval; HL, Hodgkin’s lymphoma; NHL, non-HL; OR, odds ratio; RR, relative risk.

Figure 3 Association between several specific allergic conditions and the risk of NHL.

Notes: Weights are from random-effects analysis. (A) Pooled analysis of studies on asthma. (B) Pooled analysis of studies on hay fever. (C) Pooled analysis of studies on food allergy. (D) Pooled analysis of studies on allergic rhinitis.
Abbreviations: CI, confidence interval; NHL, non-Hodgkin’s lymphoma; OR, odds ratio.

Table 2 Association between history of specific allergic conditions and the risk of NHL

Allergic conditions	Number of studies	Pooled OR/RR (95% CI)	Heterogeneity
			I^2 (%)	P-value
Asthma	15	0.94 (0.88–0.99)	16.7	0.267
Hay fever	8	0.72 (0.64–0.82)	21.7	0.257
Food allergy	6	0.71 (0.51–0.98)	84.0	<0.001
Allergic rhinitis	3	0.80 (0.73–0.88)	49.8	0.136
Dust allergy	3	0.85 (0.73–1.00)	0	0.614
Eczema	15	0.99 (0.81–1.21)	82.8	<0.001
Hives	4	1.67 (1.37–2.04)	48.2	0.122
IgE level	4	0.86 (0.49–1.49)	84.5	<0.001
Insect allergy	2	0.94 (0.64–1.37)	0	0.682
Animal allergy	3	0.83 (0.58–1.17)	58.5	0.088
Medicine allergy	5	1.06 (0.89–1.25)	64.6	0.023

Note: The OR/RR of individual study was pooled with a random-effects model if there was significant heterogeneity, otherwise a fixed-effects model was used.

Abbreviations: CI, confidence interval; NHL, non-Hodgkin’s lymphoma; OR, odds ratio; RR, relative risk.

Table 3 Association between history of allergic conditions and the risk of NHL according to the type of NHL and geographic region

Factor	Number of studies	Pooled OR/RR (95% CI)	Heterogeneity
			I^2 (%)	P-value
NHL type
B-cell NHL	8	0.74 (0.59–0.92)	73.3	<0.001
T-cell NHL	3	0.70 (0.52–0.94)	0	0.520
DLBCL	8	0.85 (0.75–0.97)	0	0.791
FL	9	0.94 (0.77–1.15)	51.1	0.037
MZL	2	0.56 (0.27–1.16)	29.5	0.234
LPL	2	0.38 (0.14–1.04)	0	0.419
Geographic region
USA and	15	0.87 (0.74–1.03)	90.6	<0.001
Canada
Europe	20	0.91 (0.81–1.02)	65.3	<0.001
Others	2	1.86 (0.35–9.89)	98.7	<0.001

Note: The OR/RR of individual study was pooled with a random-effects model if there was significant heterogeneity, otherwise a fixed-effects model was used.

Abbreviations: CI, confidence interval; DLBCL, diffuse large B-cell lymphoma; FL, follicular lymphoma; LPL, lymphoplasmacytic lymphoma; MZL, marginal zone lymphoma; NHL, non-Hodgkin’s lymphoma; OR, odds ratio; RR, relative risk.

Figure 4 Association between history of allergic conditions and the risk of HL.

Abbreviations: CI, confidence interval; HL, Hodgkin’s lymphoma; OR, odds ratio.

Table 4 Association between history of allergic conditions and the risk of HL according to the type of allergic conditions and geographic region

Factor	Number of studies	Pooled OR/RR (95% CI)	Heterogeneity
			I^2 (%)	P-value
Allergic conditions
Hay fever	3	0.71 (0.54–0.93)	57.5	0.095
Food allergy	2	0.54 (0.33–0.88)	0	0.916
Asthma	7	0.99 (0.83–1.18)	0	0.693
Eczema	4	1.21 (0.80–1.83)	56.1	0.077
Geographic region
USA and Canada	3	1.16 (0.73–1.83)	73.1	0.024
Europe	9	0.95 (0.82–1.10)	0 0.	563

Note: The OR/RR of individual study was pooled with a random-effects model if there was significant heterogeneity, otherwise a fixed-effects model was used.

Abbreviations: CI, confidence interval; HL, Hodgkin’s lymphoma; OR, odds ratio; RR, relative risk.