The association between a plant-based diet (vegetarianism) and extended life span is increasingly criticised since it may be based on the lack of representative data and insufficient removal of confounders such as lifestyles.We examined the association ...
From the study “GDP PPP may be a comprehensive life expectancy contributor. For instance, populations with greater GDP PPP may have higher meat affordability, better medical service and better education level. Each factor may contribute to life expectancy in its unique way, but it is impossible to collect all these data and include them as the potential separate confounders in the data analyses to remove their competing effects on life expectancy.”
So, I think you’re making a good point.