How to make inference from mean/sd of unknown distribution

I have some info culled from international registries of non-US rehab
medicine clinical trials

one of the questions of interest is whether a trial included subjects
over a certain age (e.g., 65 or 85); note that I do NOT have info on
the inclusion/exclusion criteria

for most trials I have the total N, but not for all trials

for some trials I have the mean and SD (though for some I only have the
mean) or I have info that can be used to estimate these values (I am
using the formulae suggested in Wan, X, et al. (2014), “Estimating the
sample mean and standard deviation from the sample size, median, range
and/or interquartile range”, BMC Medical Research Methodology, 14: 135)

If I have the N, the mean and the SD AND if I can assume that the ages
are approximately normally distributed, then answering the over65 or
over85 question is easy. However, I am uncomfortable making this
assumption and I am looking for citations that provide guidance for
either (1) different distributions (esp skewed ones) and/or (2)
truncated distributions but where the truncation point is unknown. If I
could find such cites, I could do a sensitivity analysis re: the assumed
normal distribution answer

So, does any one know of any such citations or have other suggestions?

By the way, I know that I could do a bunch of simulations to get there
but I think this would be more expensive then my clients want to go.

I note that I have received a suggestion to look at pop data to see if
distributional info for the countries where the research is taking place
can help with the assumption of normality

I ended up using Chebyshev’s inequality (some people in the group did not trust the official population age data for some countries so we did not even try to obtain it)

they are old trials, ie not registered on if the Q is: did the trial include patients older than X, then I’m not sure it’s a statistical Q. you dont have a protocol for even a single trial? or recruitment rates across ages for any similar trials? A clinical person in that field could probably answer the Q without doing any stats on it