No, the extremely reduced lifespan of Orks is well established both in multiple rulebooks over multiple editions as well in multiple books of fiction.
And while crime, poverty and diet do play a part, even an ork born to a wealthy family, lives in a zero crime area, and eats the best food available will have a very hard time seeing 40, let alone 50.
Is it fair? Nope. But who said life was fair? Orks just do not live as long as humans. And remember, an ork is NOT a human. (Very closely related, granted, but not human).
They are Orks, an entirely different species in the Homo genus. They are bigger then humans, stronger and hardier then humans, have more and larger teeth then humans (36 compared to 32). But they are not green
(But apparently an off shoot is Red skinned as I recall)
And biologically they would have to be short lived given their reproductive cycle. (6 month pregnacy, births of 2 to 12, with 4 being the average...).
If they had a human life span and reproductive span. A single couple could produce 416 children! (2 birthings a year, 4 rugrats at a time from the age of 13 to 40).
Just how quickly to you think it would take for the world to reach overpopulation when 20% of the world population is Orks?
<well, if a single family could produce 400 kids during their reproductives lives (based on a human length reproductive cycle) it would only take 3 to 4 generations....>
Now compare that to what is actually published (furtility of 10 to 28 = 18 years) is 144 kids. But again with a much shorter lifespan, meaning overcrowding is less of an issue. (It'll still happen given the high birth rate, but take much longer).
But the bigger question: how many kids actually survive to childhood? THIS is where poverty, diet, and sanitation come in. Most Orks are dirt poor. (Laid out some the reasons up top), couple the poverty with a lack of social services, and the cost of food, lack of sanitation and I imagine the death rate of infants is high. A healthy human eats about 3 to 4 pounds of food each day. Orks being bigger mass would require a little more... 4 to 6 pounds a day? So to provide for a typical birthed family, a single time (meaning 4 kids) means to survive the family is consuming 24 to 36 pounds of food a day!
To an destitute family, that is one heck of an expense! And we havn't even covered clothing or housing....