> Incidence of ARIs was documented through monthly follow-up visits and self-reported symptom diaries validated by physician assessment.
This is basically impossible to accomplish for 386 participants who aren't in some form of captivity (e.g. incarcerated, institutionalized, in the military, or a boarding school). Nobody cares enough to maintain a "self-reported symptoms diary" and make monthly visits for some study. If they actually ran the study as designed, they would've have zero usable participants even starting from 400.
Saying nothing of the ethics of giving half the Vitamin D deficient patients presenting at your clinic with a placebo.
> (e.g. incarcerated, institutionalized, in the military, or a boarding school).
That's a pretty big list. Add Retirement communities and your pool increases even more. Add to that the fact that this is India where the population is at least 5x bigger and much more concentrated..
Most retirement communities don't have that much supervision.
Regardless, you can get a lot of data, but of it is from people who have other significant differences in lifestyle from the average person and so it is questionable how it applies. Military gets more physical fitness (we already know most of us need more). Boarding school implies young - children or just older, and so while not useful there are differences related to that to control for (military as well, unless you can get officers who are older thus allowing controlling for age).
> Most retirement communities don't have that much supervision
Retirement communities in India are relatively new. Most older folks get taken care of at home by domestic staff, which, given India's demographics, are incredibly cheap and thus plentiful.
There are retirement communities in India and end-of-life care centers as well. Societies change, and thanks to the internet, societies change faster than ever.
> Incidence of ARIs was documented through monthly follow-up visits and self-reported symptom diaries validated by physician assessment.
This is basically impossible to accomplish for 386 participants who aren't in some form of captivity (e.g. incarcerated, institutionalized, in the military, or a boarding school). Nobody cares enough to maintain a "self-reported symptoms diary" and make monthly visits for some study. If they actually ran the study as designed, they would've have zero usable participants even starting from 400.
Saying nothing of the ethics of giving half the Vitamin D deficient patients presenting at your clinic with a placebo.