Probably not in many cases but its a contributing factor. And you went on to say to definitely 'eliminate anything' that could be causing low test in your next post without specifying or giving a hint as to what exactly to look at.I doubt sleep/diet/exercise problems would ever drop testosterone that low.
......
People should be uneasy about the trend of declining male fertility (sperm counts) and I wonder its related to the increased amount of chemical pollutants and gmos as a side effect of living in an industrialized world. Endocrine disrupting plasticisers (phthalates) got the ban about 2 yrs back but who knows the plasticisers that replaced it or whatever else is out there is safe. Then there is greatly increased amounts of RF waves from cellphones/cordless/wireless routers since the last decade and a half.