Height, leg length, and cancer: the Caerphilly Study.

Area of Science:

• Epidemiology
• Oncology
• Human Physiology

Background:

• Cancer incidence is known to correlate with increasing height.
• Leg length, a proxy for prepubertal growth, is hypothesized to be the primary driver of height-cancer associations.
• Prospective studies investigating this specific relationship are limited.

Purpose of the Study:

• To prospectively examine the associations between height, leg length, trunk length, and cancer incidence.
• To determine if leg length is a more significant predictor of cancer risk than overall height or trunk length.
• To investigate height-cancer associations for overall cancer and site-specific cancers, including lung cancer.

Main Methods:

• A 21-year prospective follow-up study of 2,393 cancer-free men aged 45-59.
• Measurements included height, sitting height (used to derive leg and trunk length), and covariates like socioeconomic position, smoking, and body mass index.
• Cox proportional hazards models were employed to analyze associations between anthropometric measures and cancer incidence.

Main Results:

• Overall height showed a weak, non-significant positive association with cancer incidence (HR 1.09 per SD increase).
• Leg length demonstrated a slightly stronger, though still weak, positive association with cancer incidence (HR 1.09) compared to trunk length (HR 1.05).
• Height-cancer associations were most pronounced for lung cancer (HR 1.21).

Conclusions:

• The study provides limited evidence supporting the hypothesis that leg length underlies height-cancer associations.
• While weak, the positive association between leg length and cancer incidence warrants further investigation.
• Height, particularly leg length, may be a modest risk factor for certain cancers, notably lung cancer.