What causes incontinence, is it lifestyle, or biological?

Childbirth can. In many women the problems develop from childbirth but do not appear till years after delivery of multiple or large babies. To know if she has incontinence and what treatments are available, a woman should overcome shyness and tell her gyn provider. A referral to a urogynecologist might be needed also.
Yes. Genetics effect support tissue (collagen). Tobacco weakens collagen. Obesity and chronic straining (heavy lifting and constipation) put pressure and weaken, vaginal delivery can cause trauma to the tissue. Urge incontinence is effected by caffiene and possibly acidic beverages.