Table 3

Study characteristics

Setting Sample size Sample age range Definition of obesity Outcome measure and covariates Results
Perry DC et al. 33
Scotland597 017 children
(distribution by sex and ethnic background unreported)
Age 5–6 to 18 years, diagnosis of SCFE or censor date (December 2016)Age-specific and sex-specific BMI standardised to UK90 reference population
Underweight <5th percentile, overweight ≥85th percentile, obese ≥95th percentile
Mild/moderate obesity ≥95th–99th percentile, severe obesity ≥99th percentile
Diagnostic record of SCFE (ICD10 M93.0 or ICD9 732.2) in linked hospital admission records
Covariates included in adjusted model: age, sex, quintile of SES deprivation
Adjusted IRR for SCFE was: 5.9 (3.9, 9.0) among those with severe obesity, 3.8 (2.6, 5.8) among those with mild/moderate obesity, 1.5 (0.9, 2.3) among those with overweight
Ortiz-Pinto MA et al.34
Madrid, Spain1884 children
(50.8% male; distribution by ethnic background unreported)
Age 4 to 6 yearsAge-specific and sex-specific BMI standardised to WHO 2006 reference tables
Overweight z-BMI >+1 SD and ≤+2 SD, obese z-BMI >+2 SD
Abdominal obesity based on waist-to-height ratio was defined as ≥90 th percentile
Abdominal obesity based on waist circumference defined as ≥90 th percentile reference tables by Fernandez et al 33
Visits to doctor offices relating to musculoskeletal system coded using International Classification of Primary Care −2 Classification
Covariates included in adjusted model: -sex, age, maternal educational level, familial purchasing power, time breastfeeding, perceived health status at age 4 years
Adjusted IRR for musculoskeletal complaints: 1.3 (1.0,1.6) among children with abdominal obesity based on waist-to-height ratio, compared with children with no abdominal obesity
Adjusted IRR for musculoskeletal complaints among children with obesity: 1.3 (0.9,1.8) and with overweight (1.1; 0.9,1.4) based on z-BMI as indicator of obesity
Palmer AJ et al.14
Catalonia, Spain466,997 children
(51.4% male; 89.0% Spanish, 11.0% other nationality)
Age 4 to 15 years, migration out of area, death or censor date (2016)Age-specific and sex-specific BMI standardised to WHO 2007 guidance
Underweight ≤2 SDs, normal weight −2 to +2, overweight >+2 and obesity >+3
Lumbar spine pain (ICD-10: M54.1, M54.3, M54.4, M54.5) thoracic back pain (M54, M54.6, M54.8, M54.9) or cervical spine pain (M54.2) recorded in paediatric primary care clinics
Covariates included in adjusted model: age, sex, SES, nationality
Cumulative incidence of any back pain by weight status: 8.8% (8.5, 9.1) normal weight, 10.1% (8.9, 11.4) overweight, 11.8% (9.4,14.2) obese
Univariable HR for back pain: 1.2 (1.1, 1.3) for children with overweight and 1.3 (1.2, 1.5) for those with obesity compared with normal weight
Adjusted HR for back pain: 1.2 (1.1, 1.3) for children with overweight and 1.3 (1.2, 1.5) for those with obesity compared with normal weight
Lane JCE et al.15
Catalonia, Spain466 997 children
(51.4% male; 89.0% Spanish, 11.0% other nationality)
Age 4 to 15 years, migration out of area, death or censor date (2016)Age-specific and sex-specific BMI standardised to WHO 2007 guidance
Underweight ≤2 SDs, normal weight −2 to +2, overweight >+2 and obesity >+3
Fractures recorded using Interntional Classification of Diseases-10 codes in primary care
Covariates included in the adjusted model: sex, age, socioeconomic status, nationality
Cumulative incidence for fracture by weight status: 10.1% (9.8, 10.3) normal weight, 11.3% (10.2, 12.4) overweight, 13.1% (10.7, 15.4) obese
Univariable HR for fractures: 1.1 (1.1,1 .2) for children with overweight and 1.3 (1.2, 1.4) for those with obesity compared with normal weight
Adjusted HR for fractures: 1.1 (1.1, 1.2) among children with overweight and 1.2 (1.1, 1.3) among children with obesity compared with normal weight children
  • BMI, body mass index; IRR, incidence rate ratios; SCFE, slipped capital femoral epiphysis.