How is adult height estimated in individuals?

Estimation of Adult Height

Adult height is estimated using the Tanner formula based on mid-parental height: for boys, (Mother's height + Father's height + 13) ÷ 2, and for girls, (Mother's height + Father's height - 13) ÷ 2, with an expected range of ±10 cm around this target. 1, 2

Primary Calculation Methods

Standard Tanner Formula (Mid-Parental Height Method)

For boys:

• Formula: (Mother's height + Father's height + 13) ÷ 2 3, 1
• Example: Parents with heights of 155 cm and 160 cm yield predicted height of 164 cm (range 154-174 cm) 1

For girls:

• Formula: (Mother's height + Father's height - 13) ÷ 2 3, 1
• Example: Same parental heights yield predicted height of 151 cm (range 141-161 cm) 1

Alternative Molinari Formula

This method accounts for secular trends (children being taller than parents by approximately 3.8 cm per generation): 3

For boys:

• Formula: (Mother's height + Father's height + 10) ÷ 2 3, 1

For girls:

• Formula: (Mother's height + Father's height - 26) ÷ 2 3, 1

Bone Age Assessment for Growth Potential

Radiography of the left wrist is the gold standard for assessing remaining growth potential and should be performed when evaluating growth concerns. 3, 1

• Bone age assessment improves prediction accuracy beyond parental height calculations alone 1, 2
• The degree of epiphyseal closure determines how much growth remains 3
• Bone age can be assessed using Greulich-Pyle, Tanner-Whitehouse (TW3), or Fels methods 4, 5

Growth Velocity Monitoring

Serial height measurements over minimum 6-month intervals are more valuable than single measurements for assessing growth patterns. 3, 1

• Calculate height velocity and compare to age-appropriate standards 3
• Growth velocity below the 25th percentile warrants investigation 3
• Growth velocity above the 75th percentile indicates catch-up growth 3
• Crossing multiple centile lines between ages 3 years and adolescence suggests pathologic process 3

Critical Assumptions and Limitations

These predictions assume:

• Both parents are healthy without chronic diseases affecting growth 1, 2
• The child has no underlying medical conditions 1, 2
• Normal nutrition and metabolic status throughout childhood 1, 2
• No significant endocrine disorders present 3

When to Investigate Further

Consider evaluation for growth disorders if: 1, 2

• Child's actual height deviates significantly from predicted target height 1, 2
• Growth velocity is abnormal for age 1, 2
• Bone age shows significant advancement or delay (>2 years discrepancy) 3
• Height falls below 3rd percentile or more than 2 standard deviations below mean 3
• Crossing downward through multiple centile lines after age 3 years 3

Accuracy of Prediction Methods

For children with constitutional delay or short stature:

• Tanner-Whitehouse methods tend to underestimate adult height by 2-7 cm 6, 4
• Bayley-Pinneau method tends to overpredict adult height by 1-3 cm 6, 7
• Roche-Wainer-Thissen method provides accurate predictions in boys (error -0.6 cm) but overpredicts in girls (+2.3 cm) 6
• Prediction accuracy improves as bone age approaches maturity 4

Special Populations

For children with chronic kidney disease:

• Standard adult height prediction methods are not recommended 3
• Growth potential assessment requires bone age plus consideration of disease-specific factors 3

For children with early puberty:

• Tanner-Whitehouse TW3 method is most accurate (92.9% predictions within ±5 cm of actual height) 5
• Predictions are more accurate when bone age is more advanced 5