The role of nutrition and genetics as key determinants of the positive height trend.
Level 4 - case-series / case-control
Cross-sectional ecological correlation study across 45 countries (by design analogy, not clinical CEBM).
PubMed 25190282 · doi:10.1016/j.ehb.2014.07.002
What was done
Ecological study comparing average height data of young men across 45 countries (Europe, Australia, New Zealand, and USA) with national-level metrics: long-term food consumption averages from the FAOSTAT database, development indicators from the World Bank and CIA World Factbook, and population frequencies of select genetic markers (Y haplogroups I-M170 and R1b-U106, as well as lactose tolerance phenotypic distribution).
What was found
The abstract reports relational directions without exact numerical statistics or effect sizes. The ratio of high-quality protein intake (dairy, pork, fish) to low-quality protein intake (wheat) was identified as the strongest explanatory dietary factor. Genetic marker frequencies (I-M170, R1b-U106, and lactose tolerance) appeared comparably important. Moderately significant positive correlations were observed with GDP per capita, health expenditure, and urbanization (specifically in Western Europe), whereas height correlated inversely with child mortality and the Gini index.
Why it matters
Highlights the potential combined contributions of protein quality, socioeconomic development, and population genetics in explaining national-level height variations among populations of European descent.
Limits
The abstract provides no exact numerical results, effect sizes, or confidence intervals. Country-level ecological associations are vulnerable to ecological fallacy and residual confounding, precluding causal inference. Findings are restricted to young men in 45 predominantly European-descended populations, and genetic marker data were more limited than nutritional metrics.
Cited by
- partial Studies indicate that high dairy intake in Scandinavia is beneficial and explains why populations there are tall and lean.