There’s a UK study (called Eurodisc) that looks into these questions, see:
http://www.physiol.ox.ac.uk/EURODISC/
Intervertebral Disc Degeneration: Interplay of Age, Environmental and Genetic Factors
Also, an interesting Chinese study:
http://english.people.com.cn/200403/...0_137044.shtml
A survey by the University of Hong Kong (HKU) shows genetic mutation is one of the causes of degenerative disc disease in Chinese people.
From PubMed:
Familial predisposition for lumbar degenerative disc disease. A case-control study.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retri...589542&dopt=Abstract