Association of premature birth and maternal education level on attention deficit hyperactivity disorder in children: A meta-analysis

Table 1 Characteristics of the included studies

Ref.	Area	Sort	Intervention	Period	Age	Sample size	Sample source	NOS score	Language	Diagnostic basis
Kong et al[25], 2024	Finland	Prospective cohort study	Premature	1996-2018	4-22	57236	N/A	7	English	ICD-10 codes
Perapoch et al[27], 2021	Spain	Retrospective cohort study	Premature	1995-2007	7-19	7488	N/A	9	English	ICD-10
Bora et al[28], 2014	New Zealand	Retrospective cohort study	Premature	1998-2000	9	217	N/A	8	English	SDQ
Cherkes-Julkowski[26], 1998	N/A	Prospective cohort study	Premature	N/A	11	48	N/A	8	English	Stanford-Binet, 4th
Huang et al[16], 2018	China	Retrospective cohort study	Education level of mother	2013-2014	6-12	270	Multicenter	9	Chinese	DSM-5
St Sauver et al[33], 2004	United States	Case control study	Education level of mother	1976-1982	14-20	5701	Multicenter	7	English	DSM-4
Rydell[32], 2010	Sweden	Prospective cohort study	Education level of mother	None	10	1206	Single center	9	English	DSM-4
Chen et al[29], 2024	China	Retrospective cohort study	Education level of mother	2022-2023	6-12	11190	Multicenter	7	English	Parent Symptom Questionnaire
Hsu et al[31], 2022	Taiwan, China	Retrospective cohort study	Education level of mother	2000-2011	6-11	1855	Multicenter	5	English	DSM-IV-TR
Yan et al[35], 2018	China	Cross-sectional	Education level of mother	2014	3-6	15291	Single center	7	Chinese	Conners concise questionnaire
Cochran et al[30], 2022	United States	Prospective	Education level of mother	2002-2004	10-15	1010	Multicenter	9	English	Child Symptom Inventory-4
van Dyk et al[34], 2015	South Africa	Case control	Education level of mother	N/A	5-13	100	Single center	6	English	DSM-4

NOS: Newcastle-Ottawa Scale; N/A: Not applicable; ICD: International Classification of Diseases; SDQ: Strengths and Difficulties Questionnaire; DSM-4: Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition.

Table 2 Summary of meta-analysis results of the influence of premature delivery and mother’s education level on attention deficit hyperactivity disorder

Intervention measure	Item	Z	OR	95%CI	P value	I2
Premature	Premature vs term	21.13	2.76	2.52-3.04	< 0.001	1.9%
	Very premature vs mild-late premature	3.66	1.95	1.37-2.79	< 0.001	87.3%
Education level of mother	≥ 12 years vs < 12 years	1.56	0.78	0.57-1.07	0.119	91.7%
	≥ 12 years vs < 9 years	2.19	0.61	0.39-0.95	0.029	84.5%
	≥ 12 years vs < 9 years1	4.98	0.59	0.48-0.73	< 0.001	47.1%
	≥ 12 years vs 9-12 years	2.40	0.74	0.58-0.95	0.016	77.6%
	9-12 years vs < 9 years	1.44	0.74	0.49-1.11	0.150	59.2%

¹Eliminate the literature with great heterogeneity.

OR: Odds ratio; CI: Confidence interval.

Table 3 Assessment of quality of studies by the Newcastle-Ottawa scale

Ref.	Selection			Comparability			Outcome			Score
	1	2	3	4	5a	5b	6	7	8
Kong et al[25], 2024	1	1		1	1		1	1	1	7
Perapoch et al[27], 2021	1	1	1	1	1	1	1	1	1	9
Bora et al[28], 2014	1	1	1	1	1	1	1		1	8
Cherkes-Julkowski[26], 1998	1	1	1	1	1	1		1	1	8
Huang et al[16], 2018	1	1	1	1	1	1	1	1	1	9
St Sauver et al[33], 2004	1	1	1		1	1	1		1	7
Rydell[32], 2010	1	1	1	1	1	1	1	1	1	9
Chen et al[29], 2024		1	1	1	1	1	1		1	7
Hsu et al[31], 2022	1		1		1	1			1	5
Yan et al[35], 2018	1		1	1	1	1		1	1	7
Cochran et al[30], 2022	1	1	1	1	1	1	1	1	1	9
van Dyk et al[34], 2015		1	1	1	1	1			1	6

1: The exposed cohort is representative; 2: Study cohort with unexposed; 3: Exposure factor identified; 4: No positive results at the start of the study; 5: Cohort comparability based on design or analysis (a: Study age controls; b: Study controls for any additional factors); 6: Outcome assessment is reliable; 7: Follow-up time is long enough; 8: Adequacy of cohort follow-up.

Table 4 Subgroup analysis summary table of mothers’ education years ≥ 12 years vs < 12 years

Analysis specification	Z	OR	95%CI	P value	I2
All	1.56	0.78	0.57-1.07	0.119	91.7%
China	4.21	0.59	0.46-0.75	< 0.001	81.2%
Other	0.68	1.25	0.66-2.40	0.495	92.3%
Multicenter	1.52	0.67	0.41-1.12	0.128	94.2%
Single	0.11	0.97	0.59-1.61	0.912	86.2%

OR: Odds ratio; CI: Confidence interval.

Table 5 Summary of publication bias

Intervention measure	Item	Incorporate literature	t	P value	95%CI
Premature	Premature vs term	4	0.67	0.570	-3.02 to 4.13
Education level of mother	≥ 12 years vs < 12 years	8	0.57	0.591	-4.91 to 7.88
	≥ 12 years vs < 9 years	6	-0.13	0.905	-4.90 to 4.49
	≥ 12 years vs < 9 years1	3	-3.29	0.188	-10.13 to 5.96
	≥ 12 years vs 9-12 years	6	-0.93	0.405	-10.85 to 5.41
	9-12 years vs < 9 years	4	-1.28	0.330	-9.43 to 5.11

¹Eliminate the literature with great heterogeneity

CI: Confidence interval.

Table 6 Summary of meta-regression

Condition	t	P value	OR	95%CI
Merge	0.45	0.686	0.78	-4.81 to 6.38
Quality	0.21	0.894	0.04	-0.58 to 0.66
China	3.10	0.053	3.16	-6.40 to 0.09
Age1	2.33	0.102	2.60	-0.96 to 6.17
Multicenter	0.17	0.876	0.09	-1.56 to 1.74

¹The groups were divided by age: Children aged 10 were included in the control group, while the intervention group consisted of samples with ages above 10.

OR: Odds ratio; CI: Confidence interval.