Sex differences in lung growth and development in childhood, adolescence, and early adulthood
| Age (years) | Somatic and lung growth patterns | Sex differences in somatic and lung growth and physiology | ||
|---|---|---|---|---|
| Childhood | ||||
| 1–2 years |
Somatic growth: ∼ linear with age Lung growth: Alveolar multiplication continues at least until age 2, possibly longer, distal airways grow faster than central airways,24 33 trachea grows faster than in utero38 | Lung growth: Lung size continues to increase at least until growth of the chest wall is complete33; female lungs are smaller than male lungs based on morphometry15 | ||
| Physiology: Females have larger airways in relation to lung size than males,15 specific airway resistance lower at any given height in females than in males39 | ||||
| Up to ∼6 years | Somatic growth: ∼linear with age | Lung growth: See above under 1–2 years15 | ||
| Lung growth: Appears to be dysanaptic from early childhood as reflected in airway parenchymal somatic growth patterns24 25 | Physiology: Specific airway resistance lower in females than in males at any given height39 | |||
| ∼6 to ∼10 years |
Somatic growth: See above under up to ∼6 years Lung growth: See above under up to ∼6 years25 | Lung growth: See above under 1–2 years.15 Females exhibit a non-linear acceleration of growth of FEF25–75/FVC and males a slowing of its growth between ages 8–10.29 Large airways grow proportionately to lung volume in females but lag in males whereas small airways grow faster than lung volume in females but proportionately in males36 | ||
| Physiology: After a deep inspiration Vmax increases in females but not in males.35 Controlling for FVC, forced expiratory flow rates are higher in females than males30 31 | ||||
| Adolescence and early adulthood | ||||
| ∼10 to mid teens |
Somatic growth: Accelerates with age; peak velocity for height occurs at age ∼11.4 in girls and at age ∼13.5 in boys and precedes peak velocity for growth of lung volume by ∼1 year (SD ∼1 year)26
43
Lung growth: Accelerates with age; peak velocity for volumes precedes peak velocity for flow rates by ∼1 year; FVC does not grow at same rate as TLC42 |
Somatic growth: See above under 1–2 years.15 Height ceases to increase with age by ∼16 years (range 8–17) in females and slows at ∼18 years in males30
31; females generate lower respiratory pressures at all ages than males49
Lung growth: Growth velocity for FVC peaks at age ∼12 (range 8–17) in females and at age ∼14 (range 10–16) in males42 Physiology: Specific airway resistance decreases up to age ∼18 in females, not in males.39FEV1 and FEV1/FVC higher in females than males, but not peak flow rates49 | ||
| Mid to late teens | Somatic growth: As above for age ∼10 to mid teens26 42; duration of growth spurt similar regardless of early, middle or late maturity42 Lung growth: As above for age ∼10 to mid teens26 42 | Somatic growth: See above for age ∼10 to mid teens30-32 41 | ||
| Lung growth: Growth velocity for FVC plateaus in females after height ceases to increase with age, but continues at a slower pace in males till the mid 20s, attributed to a muscularity effect.49 Growth of TLC, and of flow rates relative to TLC slower in females than in males, i.e. growth appears to be dysanaptic in females and isotropic in males in most but not all studies26 33 | ||||
| Physiology: See above under ∼10 to mid teens:girls generate lower pressures than boys at all lung volumes49; effort independent flows higher in females than males, but not peak flows.49 RV/TLC% higher in females than males and increases with age43 | ||||
| Late teens to ∼mid 20s |
Somatic growth: Height stable but weight increases Lung growth: Linear age related increase in lung function slows with the end of the adolescent growth spurt33 | Somatic growth: Ceases in teens in females, continues in males but at a slower rate than in the teens30 31 | ||
| Lung growth: See above under mid to late teens26 33 49 | ||||
| Physiology: See above under mid to late teens30 39 43 | ||||
Compiled from references 15, 24–27, 29–31, 39–43.
FEF = forced expiratory flow rate; TLC= total lung capacity; FVC= forced vital capacity; FEV1 = forced expiratory volume in one second.