One of the inherited risk factors for varicose veins is a positive family history of varicose veins.
Occupations that involve lots of standing are also a risk factor for developing varicose veins.
Being pregnant and having a high BMI can also exacerbate varicose veins.
Thread veins can be idiopathic or secondary to hormonal changes. Thread veins on legs may be associated with venous reflux or varicose veins.
Sun worshipers may notice that they also develop spider veins because of damage to the collagen.