Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
Evol Med Public Health. 2013 Jan;2013(1):106-17. doi: 10.1093/emph/eot007. Epub 2013 Apr 18.
The thrifty phenotype hypothesis proposes that late-life metabolic diseases result from mismatch between early-life and adulthood nutrition. More recently, the predictive adaptive response (PAR) hypothesis has suggested that poor early-life environmental conditions induce metabolic changes that maximize health and fitness in similarly poor adult conditions, but reduce fitness if conditions later improve. Therefore, later-life survival and reproduction should be maximized where environmental conditions during development and adulthood match, but few studies in humans have addressed the consequences of poor early conditions on fitness traits in varying later conditions.
We tested key evolutionary predictions of the PAR hypothesis using detailed longitudinal data with several environmental parameters from a natural fertility preindustrial human population, to investigate how combinations of early- and late-life environmental conditions affected annual probabilities of survival and reproduction.
We found no suggestion that fitness was maximised when developmental and later-life conditions matched, but rather poor environmental conditions during development or later life and their combinations were associated with lower survival.
Our results are more consistent with predictions of 'silver spoon' models, whereby adverse early-life conditions are detrimental to later health and fitness across all environments. Future evolutionary research on understanding metabolic disease epidemiology should focus on determining whether adaptive prediction maximizes infant survival where conditions match during development and immediately after birth, rather than drawing attention to the unlikely long-term fitness benefits of putative metabolic changes associated with poor early nutrition.
节俭表型假说提出，老年期代谢疾病是由早期生活和成年期营养之间的不匹配引起的。最近，预测适应性反应（PAR）假说表明，恶劣的早期环境条件会诱导代谢变化，使成年期相似恶劣条件下的健康和适应能力最大化，但如果条件随后改善，则会降低适应能力。因此，在发展和成年期的环境条件相匹配的情况下，后期的生存和繁殖应该最大化，但很少有人类研究关注早期条件差对不同后期条件下适应能力特征的影响。
我们使用来自自然生育前工业化人群的详细纵向数据和几个环境参数，检验了 PAR 假说的关键进化预测，以研究早期和后期环境条件的组合如何影响年度生存和繁殖的可能性。
我们没有发现当发展和后期条件匹配时适应能力最大化的迹象，而是发现发展过程或后期生活中的恶劣环境条件及其组合与较低的生存能力相关。
我们的结果与“银汤匙”模型的预测更为一致，即恶劣的早期条件对所有环境中的后期健康和适应能力都有害。未来关于代谢疾病流行病学的进化研究应侧重于确定在发展和出生后立即匹配的条件下，适应性预测是否能最大限度地提高婴儿的生存能力，而不是关注与不良早期营养相关的潜在代谢变化的长期适应能力益处。
