Knowing the factors contributing to varicose veins in the lower extremities is important for prevention. Few reliable epidemiological studies have been done so far. They have led to beliefs rather than certainties
It is a clear contributing factor: estrogens, which are released during pregnancy throughout the body, especially during the last three months, are more of a contributing factor than the pressure exerted by the foetus on the abdominal venous system in the last three months of pregnancy. The link between pregnancy and varicose veins must take into account the maternal age, the weight gain and especially the number of previous pregnancies, the risk of varicose veins increasing significantly with the number of pregnancies.
The role of contraceptive pills varies considerably from one patient to another and according to the hormonal change they trigger. The more estrogenic pills, and not necessarily those with the highest doses, seem to cause more venous function problems than other pills.
Two varicose veins out of three seem to have a genetic origin.
Studies done on tissue changes in the wall of varicose veins point at the existence of a genetic link, but it is difficult to differentiate between the genetic and the acquired part in the metabolic and biochemical changes observed.
The HLA B7 groups seem to be affected more often, whereas the HLA aw 19 and cw5 groups seem to be spared more often.
Looking at the geographical distribution of varicose veins in the lower extremities, one could suspect a race factor. This factor has not been confirmed in patients coming from low-incidence zones and moving to industrialized countries. It has been shown that after one or two generations, they have the same incidence of varicose veins as the local population. This supports the view that lifestyle is a much more important factor than race.
In addition to physical inactivity to which it contributes, weight plays a role in venous circulation through the formation of adipose panicules which deprive the veins of their muscular support.
The influence of lifestyles is one of the most difficult elements to study. There are, in any case, clear geographical differences in the world distribution of varicose veins.
The prevalence of varicose veins increases with the level of industrialisation. There is also a difference in the distribution of varicose veins in the cities and in the countryside, probably linked to physical activity.
As a rule, there is an indisputable link between varicose veins and physical inactivity, reduced muscular effort, jobs with prolonged standing or sitting positions, exposure to heat and diet-induced weight gains.
Lack of physical activity, as we saw, plays a direct role in venous insufficiency due to lack of muscular activity but also an indirect one through overweight. Participating in a sport is highly recommended.
However, although biking, walking and swimming are considered excellent, competition sports, sports involving holding breath under exertion (weight lifting for instance), sports that can lead to direct blows to the legs (wrestling), and sports involving abrupt stops or acceleration (tennis), must be played in moderation.
Any piece of clothing that could hinder the venous flow should be avoided. One should avoid in particular clothes that constrict the legs or thighs.
High-heel shoes or shoes that are too flat should also be avoided as their frequent use can lead to static changes in the plantar arch.
Heat has a negative effect on the vein wall by increasing its dilatation.
However, many hot countries have a low incidence of varicose veins.
A diet rich in fibres is favourable to venous circulation since it decreases constipation, an aggravating factor.
The role of free radicals is fashionable today. Vitamin E, which protects the vein wall and is found in many venotonics such as flavonoids, is thought to act directly on the free radicals damaging to the veins.