In the initial search, a total of 595 articles were found in related databases (with 78 in Web of Science, 118 in PubMed, 112 in Embase, and 287 in Scopus). After a preliminary review and the elimination of duplicates, 467 papers were screened and chosen for further evaluation. A total of 18 studies were included in this study after applying the inclusion/exclusion criteria. Only an adjusted OR for neuroblastoma following high birth weight was reported in one research [20] and an unadjusted OR could not be determined from the data. Another study [21] had to be removed due to significant case overlap with a prior study. In one paper [22], since both USA and UK data were reported, it was assumed that this research represents separate studies in the quantitative analysis. In addition, since only low birth weight OR was reported in one study [23] and only high birth weight OR was also reported in one study [24], the relevant studies were added to the analyses separately. As a result, a total of 16 papers (Fig. 1) could be used for meta-analysis [10–13, 22–33] The major parameters of the included studies are available in Table 1.
Table 1
Distribution of included studies by country, design, birth year (s), diagnosis year(s), age at diagnosis (years), and number of cases/controls
Study (First author (year))
|
Country
|
Design
|
Birth year(s)
|
Diagnosis year(s)
|
Diagnosis
age (years)
|
Number of
cases/controls
|
Bjorge (2008) (25)
|
Norway
|
Cohort
|
1967–2004
|
1967–2004
|
0–15
|
Cohort: 2,127,452
|
Bluhm (2008) (26)
|
Sweden
|
Case-control
|
1973-95
|
1973-95
|
NA
|
245/1,225
|
Buck (2001) (10)
|
USA
|
Case-control
|
1971-87
|
1976–87
|
0–5
|
310/155
|
Chow (2007) (27)
|
USA
|
Case–control
|
1980–2004
|
1980–2004
|
NA
|
240/2,400
|
Hamrick (2001) (28)
|
USA, Canada
|
Case–control
|
1974–94
|
1992–94
|
0–18
|
504/504
|
Johnson and Spitz (1985) (23)
|
USA
|
Case-control
|
1949–78
|
1964–78
|
0–14
|
157/314
|
Johnson (2008) (29)
|
USA
|
Case-control
|
1976–2004
|
1988–2004
|
0–14
|
155/8.752
|
McLaughlin (2008) (11)
|
USA
|
Case-control
|
1983–2001
|
1985–2001
|
0–14
|
529/12,010
|
Munzer (2008) (12)
|
France
|
Case-control
|
1989–2004
|
2003–04
|
0–14
|
191/1,681
|
Neglia (1988) (24)
|
USA
|
Case-control
|
NA
|
NA
|
0–9
|
97/388
|
O'Neill (2015) (22)
|
USA
|
Case-control
|
1970–2004
|
1980–2004
|
0–14
|
16,554/53,716
|
O'Neill (2015) (22)
|
UK
|
Case-control
|
1980–2007
|
1980–2007
|
0–14
|
23,772/33,206
|
Parodi (2014) (30)
|
Italy
|
Case-control
|
1998–2001
|
1998–2001
|
0–10
|
153/1,044
|
Rios (2016) (31)
|
France
|
Case-control
|
NA
|
2003-2004-2010-2011
|
0–15
|
357/1,783
|
Schuz (1999) (32)
|
Germany
|
Case-control
|
1978–94
|
1992–94
|
0–14
|
183/1,785
|
Uruyama (2007) (13)
|
USA
|
Case-control
|
1983–97
|
1988–97
|
0–4
|
508/1,015
|
Heck (2020) (33)
|
Taiwan
|
Cohort
|
2004–2014
|
2004–2014
|
0–14
|
Cohort: 2,079,037
|
NA: not available |
Table 2
Descriptive and clinical features of included studies in the meta-analysis
Study (First author)
|
Source of controls
|
Source of case diagnosis
|
Source of data for birth weight
|
Original study results
|
Bjorge (2008) (25)
|
NA (cohort: population)
|
Cancer registry
|
Birth registry
|
“Unadjusted risk ratio (95% CI) for birth weight 4000–4499 g (vs 3000–3499 g): 1.4 (0.9–2.1); for birth weight < 2500 g: 0.6 (0.2–1.9)”
|
Bluhm (2008) (26)
|
Birth registry
|
Swedish Cancer Register or Death Register.
|
National Cancer Register
|
“OR (95% CI), adjusted for birth year, for birth weight > 4500 g (vs 2500–4499 g): 1.07 (0.53–2.18); for birth weight < 2500 g: 1.05 (0.51–2.19)”
|
Buck (2001) (10)
|
Birth registry
|
Cancer registry
|
Birth certificates
|
“Unadjusted OR (95% CI) for birth weight > 4000 g (vs 3000–3499 g): 1.2 (0.6–2.2); for birth weight
< 2500 g: 0.9 (0.4–2.2)”
|
Chow (2007) (27)
|
Birth certificates
|
Cancer registry
|
Birth certificates
|
“OR (95% CI), adjusted for birth year, for birth weight > 4000 g (vs 2500–3999 g): 1.25 (0.87–1.79); for birth weight < 2500 g: 0.75 (0.38–1.51)”
|
Hamrick (2001) (28)
|
Random digit dialing
|
Clinical recordsa
|
Interview
|
“OR (95% CI), adjusted for gender, race, maternal education, and household income, for birth weight 4001–4499 g (vs 2501–4000 g): 1.1 (0.7–1.7); for birth weight 1500–2500 g: 1.1 (0.6–2.0)”
|
Johnson and Spitz (1985) (23)
|
Birth certificates
|
Death certificates
|
Birth certificates
|
“Unadjusted OR (95% CI) for birth weight < 2500 g (vs 4380 g): 3.22 (1.13–9.20)”
|
Johnson (2008) (29)
|
Birth registry
|
Cancer surveillance
|
Birth records
|
“Hazard ratio (95% CI), adjusted for sex and birth year, for birth weight 4000 g (vs 2500–4000 g): 1.10 (0.70–1.73); for birth weight < 2500 g: 1.17 (0.60–2.28)”
|
McLaughlin (2008) (11)
|
Birth certificates
|
Cancer registry
|
Birth certificates
|
“Risk ratio (95% CI), adjusted for birth year, region, gender, and race, for birth weight 44500 g (vs 2500–3499 g): 1.4 (0.7–2.5); for birth weight < 2500 g: 1.5 (1.0–2.1)”
|
Munzer (2008) (12)
|
Random digit dialing
|
Cancer registry
|
Interview
|
“OR (95% CI), adjusted for age and gender, for birth weight 4000 g (vs 3000–3499 g): 1.6 (0.9–2.8); for birth weight < 2500 g: 1.8 (0.8–3.8)”
|
Neglia (1988) (24)
|
Birth certificates
|
Clinical records
|
Birth certificates
|
“Unadjusted OR (95% CI) for birth weight 4000 g (vs < 4000 g): 0.96 (0.47–1.73)”
|
O'Neill (2015) (22)
|
Birth records
|
Cancer registry
|
Birth certificates
|
“OR adjusted for gestational age, birth order, plurality, maternal age, and race/ethnicity for birth weight > 4000 g (vs 3000–3999) 1.22 (1.02–1.45); for birth weight < 2500 1.36 (0.96–1.93)- 1.14 (0.87–1.51)”
|
O'Neill (2015) (22)
|
Birth records
|
National Cancer Register
|
Birth records
|
“OR adjusted sex, period, and region of birth for birth weight > 4000 g (vs 3000–3999) 1.27 (0.94–1.71); for birth weight < 2500 1.31 (0.61–2.78)-0.98 (0.58–1.64)”
|
Parodi (2014) (30)
|
Birth certificates
|
Clinical records
|
Interview
|
“OR (95% CI), adjusted for birth year, for birth weight > 4000 g 1.1 (0.57–2.00); for birth weight < 2500 g: 0.59 (0.22–1.6)”
|
Rios (2016) (31)
|
Random digit dialing
|
Clinical records
|
Birth records
|
“OR (95% CI), adjusted for age and sex, birth-order, maternal age, urban status of the area of residence and study birth weight 4000 g (vs 3000–3499 g): 1.4 (0.9–2.2); for birth weight < 2500 g: 1.2 (0.9–1.7)”
|
Schuz (1999) (32)
|
Population
|
Cancer registry
|
Interview
|
“OR (95% CI), adjusted for socio-economic status, for birth weight 4000 g (vs 2500–4000 g): 1.3 (0.8–2.1); for birth weight < 2500 g: 2.4 (1.2–4.8)”
|
Uruyama (2007) (13)
|
Birth registry
|
Cancer registry
|
Birth certificates
|
“Unadjusted OR (95% CI) for birth weight (term) 4000 g (vs 2500–4000 g): 1.25 (0.88–1.78); for birth weight < 2500 g (term): 1.40 (0.65–3.04)”
|
Heck (2020) (33)
|
NA (cohort: population)
|
National Cancer Register
|
Birth registry
|
“HR (95% CI) Adjusted mother’s age, father’s age, family income, for birth weight > 4000 g (vs 2,500–3,999g): 0.77 (0.25–2.42); for birth weight < 2500 g: 0.79 (0.42–1.45)”
|
NA: not available |
a Cases came from two collaborative clinical trial groups. |
A total of 4,361,141 participants were involved in the research, Two of the 16 studies were cohort, and the other 14 studies used a case–control strategy with matching ratios ranging from 1:1 to 1:10 in case–control studies. The initial research came out in 1985, and the most current one came out in 2020. The research was carried out in the “United States, Canada, France, Norway, Sweden, Italy, Taiwan and Germany”. Participants varied in age from 0 to 18. The number of participants in the study ranged from 471 to 2,127,452. Cases came from cancer registries in ten of the investigations, whereas they came from other sources in the other six.
High Birth Weight And Neuroblastoma Risk
There were 15 studies [10–13, 22, 24–33] that provided data for calculating the OR (95% CI) of risk of neuroblastoma in patients with a high birth weight (> 4000 g) compared to those with lower birth weight. The forest plot with ORs with 95% CIs, as well as the pooled estimate for the risk of neuroblastoma in high birth weight participants, are presented in Fig. 2. High birth weight was associated with an increased risk of neuroblastoma. This impact measure was the same when the random-effects model and the fixed-effects model were used (OR = 1.17; 95% CI: 1.06–1.29, p = 0.002; heterogeneity: Chi2 = 2.33, df = 15, I2 = 0%, p > 0.05). Sensitivity analyses were performed by extracting each study separately. No significant change was observed among the studies (df = 15, I2 = 0%, p > 0.05) (Fig. 3). The pooled estimate was quite robust, according to sensitivity analysis (fixed-effects model): excluding individual study values resulted in pooled ORs ranging from 1.17 (95% CI: 1.05–1.29) to 1.18 (95% CI: 1.07–1.30). Visual inspection of the funnel plots (Supplementary Fig. S1), as well as Begg's test (Z value: -1.14; p = 0.255) and Egger's linear regression test revealed no evidence of publication bias (Intercept: -0.14; p = 0.609).
Low Birth Weight And Neuroblastoma Risk
15 studies [10–13, 21–26, 28–31, 35] provided data for the computation of the OR (95% CI) of risk of neuroblastoma in patients with low birth weight (< 2500 g) compared to those with birth weights more than this threshold value. Figure 4 depicts a forest plot with ORs and 95% CIs, as well as the pooled estimate of the risk of neuroblastoma following low birth weight. Low birth weight was associated with an elevated risk of neuroblastoma in both the random-effects model (OR = 1.19; 95% CI: 1.03–1.37, p = 0.017) and the fixed-effects model (OR = 1.19; 95% CI: 1.05–1.36, p = 0.007; heterogeneity: Chi2 = 16.93, df = 15, I2 = 0%, p = 0.323). Sensitivity analyses were also performed by extracting each study separately for low birth weight (df = 15, I2 = 11.42%, p > 0.05). No noticeable change was observed in the analysis results. Thus, the robustness of the analysis results was confirmed by sensitivity analysis (Fig. 5). No noticeable publication bias was observed among the included studies according to the symmetry of the funnel plot (Supplementary Fig S2), Begg's test (Z-value: -1.93; p = 0.054), and Egger's linear regression test (Intercept: -0.71; p = 0.341).
Subgroup Analysis
Subgroup analysis was used to further analyze the connection with both high and low birth weight (as region). In terms of the connection with high birth weight, region-specific pooled estimates revealed no significant differences (Table 3). The relationship with low birth weight and neuroblastoma was stronger in European research than in those conducted in the United States or Canada. The technique used to collect birth weight data had no effect on the strength of the link with high birth weight. In contrast, it had a significant impact on the link with low birth weight: studies that employed interview-based data revealed a > 45% higher risk, but those that relied on registry data had a significantly lower estimate. As seen in Table 3, although the manner of acquiring the case diagnosis had no significant effect on either the high or low birth weight estimates, the low birth weight estimate was greatly influenced by the source of controls, with registry-based studies having lesser effects.
Table 3
The association between birth weight and the neuroblastoma risk: moderator analysis
Characteristics of study
|
Category
|
High birth weight OR (95% CI)
|
Low birth weight OR (95% CI)
|
Geographic area
|
North America
|
1.16 (1.03–1.32)
|
1.18 (1.00-1.40
|
Europe
|
1.19 (1.01–1.41
|
1.27 (1.03–1.57)
|
Source of data for birth weight
|
Registry
|
1.17 (1.05–1.31)
|
1.17 (1.01–1.35)
|
Interview
|
1.21 (1.00-1.45)
|
1.45 (1.07–1.96)
|
Source of case diagnosis
|
Registry
|
1.20 (1.07–1.34)
|
1.20 (1.03–1.42)
|
Othera
|
1.09 (0.88–1.35)
|
1.24 (0.99–1.56)
|
Source of controls
|
Registry/certificate
|
1.18 (1.05–1.32)
|
1.14 (0.97–1.35)
|
Otherb
|
1.17 (0.97–1.41)
|
1.36 (1.09–1.69)
|
a Included: death certificates, records, surveillance. |
b Included: population, random digit dialing. |