Table 2.
Details of the studies from south Asia included in the meta-analysis
| Author (year) | Site of recruitment; Type of study | Country | Study population | Sample size | Tool(s) used | Age at assessment | Key outcome(s) | Quality score |
|---|---|---|---|---|---|---|---|---|
| Chaudhari (1999) [30] | Hospital; Prospective follow up |
India | Infants with BW < 2000 g discharged from Neonatal special care units and full term neonates with BW > 2500 g followed up till their 6 years of age | Children with low BW- 201 Children with normal BW-71 |
Stanford Binet Intelligence Scale (SBIS) School report card assessment |
At 6 years of age | Mean IQ score - LBW: 94.3 (13.6) - NBW: 101.38 (10.2) Proportion with abnormal IQ (score of < 85 score) - LBW: 17% - NBW: 5.6% Proportion with poor school performance (< 35% marks obtained) - LBW: 12.6% - NBW: 1.8% |
6 |
| Tandon (A)(2000) [31] | Hospital; Prospective follow up | India | Infants with BW ≤2000 g discharged from special care nursery and followed up in high risk clinics; controls were healthy term infants with BW > 2500 g followed in well baby clinics | Children with low BW:27 Children with normal BW: 28 |
Stanford Binet Intelligence Scale (SBIS); Raven’s Progressive Matrices; M.E Hertzig method of assessing signs of motor dysfunction |
Age range of 5 to 9 years; mean age of 7.0 (SD 1.1) years | Mean cognitive score - LBW: 105.6 (13.4) - NBW: 116 (11.6) Proportion with low IQ score (<25th percentile) - LBW: 18.5% - NBW: 0.0% Proportion with signs of motor dysfunction - LBW: 37% - NBW: 10.7% |
2 |
| Tandon (B)(2000) [31] | Hospital; Prospective follow up | India | Infants with BW ≤2000 g discharged from special care nursery and followed up in high risk clinics; controls were healthy term infants with BW > 2500 g followed in well baby clinics | Children with low BW:32 Children with normal BW: 29 |
Stanford Binet Intelligence Scale (SBIS); Raven’s Progressive Matrices; M.E Hertzig method of assessing signs of motor dysfunction |
Age range of 9 to 13 years; mean age of 10.6 (SD 1.2) years | Mean cognitive score - LBW: 99.6 (10.8) - NBW: 110.6 (7.3) Proportion with low IQ score (<25th percentile) - LBW: 25% - NBW: 3.4% Proportion with signs of motor dysfunction - LBW: 19% - NBW: 3.4% |
2 |
| Chaudhari (2004) [32] | Hospital; Prospective follow up | India | Infants with BW < 2000 g discharged from Neonatal special care units and full term neonates with BW > 2500 g and followed up till their 12 years of age | Adolescents with low BW- 180 Adolescents with normal BW-90 |
Weschler’s Intelligence Scale; Movement assessment battery; School report card assessment |
At 12 years of age | Mean IQ score - LBW: 89.5 (16.9) - NBW: 97.2 (14.1) Proportion with abnormal IQ (score of < 85) - LBW: 37.7% - NBW: 18.8% Proportion with poor school performance (< 50% marks obtained) - LBW: 21.6% - NBW: 10.0% Mean motor impairment score - LBW: 9.8 (3) - NBW: 7.3 (2.9) |
4 |
| Juneja (2005) [33] | Hospital; Prospective follow up | India | Term infants < 2000 g and term infants with normal birth weight (> 2500 g) | Infants with BW < 2000 g-50 Infants with BW > 2500 g-30 |
Bayley Scales of Infant Development (BSID II) | At 18 months | Mean mental development quotient - < 2000 g: 91.5 (16.9) - > 2500 g: 102 (8.4) Mean motor development quotient - < 2000 g: 93.2 (19.7) - > 2500 g: 99.5 (10.3) Proportion with adverse mental development outcome - < 2000 g: 20% - > 2500 g: 3.3% Proportion with adverse motor development outcome - < 2000 g: 24% - > 2500 g: 3.3% |
2 |
| Taneja (2005) [34] | Community; Cross-sectional | India | Children aged 12 to 18 months enrolled in a randomized controlled trial | Children with low BW- 61 Children with normal BW-116 |
Bayley Scales of Infant Development (BSID II) | At 12–18 months of age Findings of assessment at baseline used |
Mean mental development quotient - LBW: 102.2 (12.26) - NBW: 102.8 (11.03) Mean motor development quotient - LBW: 100.08 (13.97) - NBW: 101.06 (12.37) Proportion with abnormal mental score (score of < 85) - LBW: 4.92% - NBW: 5.17% Proportion with abnormal motor score (score of < 85) - LBW: 13.1% - NBW: 4.3% |
7 |
| Subasinghe (2006) [35] | Community; Cross-sectional | Sri Lanka | Preschool children within the age range of 36–54 months | Children with low BW: 12 Children with normal BW: 62 |
Early Screening Inventory for Preschoolers (ESI-P) | 36 to 54 months of age | Mean cognitive score - LBW: 63.35 (14.5) - NBW: 65.32 (15.7) Mean gross motor score - LBW: 62.7 (7.4) - NBW: 68.81 (18.1) |
3 |
| Nair (2009) [36] | Hospital; Prospective follow up | India | Adolescents with known birth weight, follow up done at 13 years of age | Adolescents with low BW-183 Adolescents with normal BW-211 |
Raven’s coloured progressive matrices | At 13 years of age | Proportion with low IQ score (≤25th percentile) - LBW: 51.4% - NBW: 41.7% |
4 |
| Sidhu (2010) [37] | Community; Cross-sectional | India | Children aged 2 to 35 months recruited from a urban center | Children with low BW: 57 Children with normal BW: 196 |
Clinical Linguistic Auditory Milestone Scale (CLAMS) | 2–35 months of age; mean age of 14.15 months | Mean Language Quotient (LQ)a - LBW: 85.07 (16.6) - NBW: 94.66 (16.6) |
3 |
| Hoque (2012) [38] | Hospital; Prospective follow up | Bangladesh | Newborns discharged from a special care baby unit and followed till 12 months of age | Infants with low BW: 25 Infants with normal BW: 80 |
Bayley Scales of Infant Development (BSID II) | At 12 months of age | Mean mental score - LBW: 114.18 (12.80) - NBW: 117.11 (12.04) Mean motor score - LBW: 96.14 (25.12) - NBW: 108.41 (19.69) |
4 |
| Khan (2012) [39] | Hospital; Prospective follow up | Pakistan | Neonates discharged from neonatal intensive care unit and followed till 6 months of age | Infants with low BW: 92 Infants with normal BW: 18 |
Denver Development Screening Test (DDST II) | At 6 months of age | Proportion with delayed development (development quotient < 60)b - LBW: 38% - NBW: 0% |
4 |
| Tofail (2012) [40] | Community; Secondary data analysis from a randomized controlled trial | Bangladesh | Live born singletons | Low BW infants- 66 Normal BW infants- 183 |
Bayley Scales of Infant Development (BSID II) | At 10 months of age | Mean mental index score - LBW: 99.5 (7) - NBW: 102.9 (8) Mean motor index score - LBW: 96.8 (10) - NBW: 102.7 (10) |
7 |
| Modi (2013) [41] | Hospital; Prospective follow up | India | VLBW admitted to a neonatal intensive care unit prospectively followed till 1 year of corrected age. A cohort of term, birth weight (≥2500 g) infants born during same period was enrolled for comparison. | VLBW-37 NBW-35 |
Developmental Assessment Scale for Indian Infants (DAS II) | At 12 months of age | Mean mental index score - VLBW: 92.9 (8.0) - NBW: 98.4 (6.1) Mean motor index score - VLBW: 90.1 (9.6) - NBW: 96.6 (5.8) |
5 |
| Chaudhari (2013) [42] | Hospital; Prospective follow up | India | Infants with BW < 2000 g discharged from Neonatal special care units and full term neonates with BW > 2500 g and followed up till their 18 years of age | Adolescents with low BW-161 Adolescents with normal BW-73 |
Raven’s Progressive Matrices | At 18 years of age | Mean IQ scorea - LBW: 39.3 (29.9) - NBW: 52.5 (29.9) Proportion with low IQ score (<25th percentile) - LBW: 24.2% - NBW: 12.7% Poor school performance (failed at least in one standard in school) - LBW: 25.5% - NBW: 5.5% |
4 |
| Avan (2014) [43] | Community; Cross-sectional | Pakistan | Low birth weight and normal birth weight infants | Low BW infants-86 Normal BW infants-566 |
Bayley Scales of Infant Development (BSID II) | Within 3 years of age | Mean psychomotor development index score - In low BW: 94.13 (18.13) - In normal BW: 98.47 (15.84) |
6 |
| Nair (2014) [44] | Hospital; Prospective follow up | India | Infants discharged from Neonatal special care units and followed up with 12 months of age | Infants with low BW- 170 Infants with normal BW-429 |
Developmental Assessment Scale for Indian Infants (DAS II) | At 12 months of age | Mean mental index scorea - LBW: 107.83 (11.04) - NBW: 110.51 (8.38) Mean motor index scorea - LBW: 99.72 (14.28) - NBW: 104.17 (10.86) |
5 |
| Christian (2014) [45] | Community; Prospective follow up | Nepal | Children aged 7 to 9 years who were part of an earlier nutrition supplementation trial | Children with low BW-764 Children with normal BW-1163 |
UNIT for general intelligence; Finger tapping test for fine motor |
At 7 to 9 years of age (mean age of 8.4 years) | Mean Intelligence score (UNIT) - LBW: 47.6 (9.4) - NBW: 51.6 (10.1) Mean fine motor score - LBW: 35.8 (5.4) - NBW: 36.9 (5.1) Mean motor impairment score - LBW: 9.98 (6.73) - NBW: 7.62 (5.59) |
8 |
| Chattopadhyay (2015) [46] | Hospital; Prospective follow up | India | Newborns discharged from SNCU | Children with low BW- 206 Children with normal BW-181 |
TDSC DDST II Visual and hearing assessment |
Under 3 years of age | Proportion with developmental delay - LBW: 38.8% - NBW: 20.9% |
4 |
| Singh (2017) [47] | Community; Cross-sectional | India | Children under 2 years of age from an urbanized village | Children with low BW- 43 Children with normal BW-153 |
Ages and Stages questionnaire, 3rd Edition | Under 2 years of age | Proportion with development delay - LBW: 16.3% - NBW: 2.0% |
4 |
| Kvestad (2017) [48] | Community; Prospective follow up | Nepal | Infants aged 2–12 months enrolled through a cross-sectional survey and followed up till 5 years of age | Children with low BW: 124 Children with normal BW: 193 |
Ages and Stages Questionnaire, 3rd edition | At 5 years of age | Mean cognitive score - LBW: 52.68 (6.9) - NBW: 51.61 (9.1) Mean motor score - LBW: 53.44 (6.1) - NBW: 53.37 (7.5) |
4 |
BW birth weight, LBW low birth weight, VLBW very low birth weight, NBW normal birth weight, IQ intelligence quotient
aSD calculated using imputation method (http://handbook-5-1.cochrane.org/chapter_7/7_7_3_3_obtaining_standard_deviations_from_standard_errors.htm)
bDevelopmental delay was assessed based on the cumulative score of developmental quotient (DQ) for each of the four domains (i.e. gross motor, language, fine motor and personal/social skills) and dividing by 4. A score of < 60 were labelled as “developmentally delayed”. DQ was calculated as, (developmental age/corrected chronological age)*100. Developmental age was established depending on the degree of achievement in each domain; UNIT-Universal Nonverbal Intelligence Test; CO = − cohort; RCT- randomized controlled trial; TDSC- Trivandrum Developmental Screening Chart; DDST- Denver Developmental Screening tool