In Neolithic times when the life expectancy was approx 30-35 in Ireland; would people have aged visibly (died of *old age*) or was death largely caused by environmental causes?

In Neolithic times when the life expectancy was approx 30-35 in Ireland; would people have aged visibly (died of old age) or was death largely caused by environmental causes?

by flaminx0r

I visited New Grange in County Meath, Ireland today and after leaving I thought of this question that I had wished I had have asked the guide/historian.

If that question requires more detail in what I'm requesting please let me know!

Thanks so much!