Adult Height as a Risk Factor for Developing Colorectal Cancer: A Population-Based Cohort Study in Thailand.

Background: Previous studies have shown that a taller stature has a higher risk of colorectal cancer (CRC) than a shorter stature. However, most prior studies were conducted in the Western region, with few studies and inconsistent results for Asians. To our best knowledge, no previous research has investigated the population of ASEAN countries, which is generally shorter in stature than the Western population. We aimed to examine the association between adult height and CRC risk in a Thai population.

Methods: This population-based cohort study was conducted in Khon Kaen, Thailand. Overall, 118 patients with CRC were histologically confirmed among 14,418 participants, who were recruited during 1990-2001 and followed up until December 31, 2020. A structured questionnaire was used to obtain baseline data, including demographic and environmental variables. The exposure of interest was measured in height and defined on the basis of the last recorded measurement. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were estimated using Cox proportional hazard regression analysis.

Results: Over a median of 21.7 years of follow-up (interquartile range: 19.9-25.6), 14,418 participants provided a total observation time of 303,899 person-years. The risk of CRC at the highest compared to the lowest height quintile was 1.29 (95% CI, 0.76-2.20; p=0.350). A trend similar to a U shape was observed (HR in Q1 vs. Q2=1.05; 95% CI, 0.62-1.75; Q1 vs. Q3=0.78; 95% CI, 0.43-1.39; Q1 vs. Q4=0.55; 95% CI, 0.29-1.05; and Q1 vs. Q5=1.29; 95% CI, 0.76-2.20).

Conclusions: Although adult height was not statistically significant, its magnitude still indicated some clues to investigate as evidence, especially for people living in the context of ASEAN countries. Large-scale, comparable studies in such contexts should be considered for confirmation.