Risk Factors of Varicose Veins

Abstract

Suonikohjutaudilla on useita riskitekijöitä

Suonikohjutauti on yleinen länsimaissa. Suomessa suonikohjujen vallitsevuudeksi on arvioitu 10 20% miehillä ja 25 40% naisilla tutkitusta ikäryhmästä riippuen. Suonikohjujen yleisyydestä huolimatta suonikohjujen syntyyn vaikuttavat tekijät tunnetaan huonosti.

Väitöstutkimuksessa selvitettiin synnyttäneisyyden, ehkäisypillereiden käytön, hormonikorvaushoidon, joidenkin elämäntapatekijöiden sekä lähisukulaisten suonikohjujen merkitystä suonikohjujen ilmaantuvuuteen. Tutkimus on osa Tampereen suonikohjututkimusta, jossa kohdeväestönä oli kolme tamperelaisista miehistä ja naisista koostuvaa ikäkohorttia, yhteensä 6874 henkilöä. Tutkimuksen alussa vuonna 1989 tutkittavat olivat 40-, 50- tai 60-vuotiaita. Tiedot kerättiin postitetuilla kyselylomakkeilla tutkimuksen alussa ja uudelleen viiden vuoden kuluttua.

Seuranta-aikana 157 aiemmin tervettä henkilöä raportoi saaneensa suonikohjuja. Niitä ilmaantui merkitsevästi enemmän niille, jotka olivat synnyttäneet vähintään kolme lasta, kun heitä verrattiin synnyttämättömiin. Tutkimuksessa havaittiin yhteys myös tupakoinnin ja suonikohjujen välillä. Erityisesti henkilöillä, jotka olivat tupakoineet paljon (?15 savuketta päivässä) oli suurentunut riski saada suonikohjuja. Yhteys havaittiin myös alkoholinkäytön ja suonikohjujen välillä, ja selvemmin naisilla kuin miehillä. Sen sijaan hormonikorvaushoidolla tai ehkäisypillereiden käytöllä ei todettu vaikutusta suonikohjujen ilmaantuvuuteen.

Niillä tutkituilla, jotka raportoivat lähisukulaisilla suonikohjuja oli noin kaksinkertainen riski saada suonikohjut seuranta-aikana verrattuna henkilöihin, jotka eivät raportoineet lähisukulaisilla suonikohjuja. Aiemmissa tutkimuksissa on yliarvioitu lähisukulaisten suonikohjujen merkitystä suonikohjujen riskitekijänä johtuen puutteellisista tutkimusmenetelmistä.

The aim of the study was to evaluate a range of potential risk factors in the etiology of varicose veins by a longitudinal follow-up study in a general middle-aged population. Studied factors were parity, use of oral contraceptives and hormone replacement therapy, lifestyle factors and self-reported family history of varicose veins. The purpose was also to evaluate misclassification in self-reported family history of varicose veins.

The five-year follow-up data was obtained through postal questionnaires from three cohorts of residents of the city of Tampere in Finland. The number of original target population of 40-, 50- and 60-year-olds was 6,874. The response rate was 81% (5,568) at entry. An almost identical questionnaire was sent five years later to those who had responded to the first questionnaire and the response rate was 88% (4,903). The questionnaire included questions related to medical conditions, lifestyle, varicose veins and family history of varicose veins. A sub-sample of subjects underwent a physical examination but family members were not clinically examined. Incidence of varicose veins was studied as an indicator of risk in those free of varicose veins at entry.

It was found that new varicose veins appeared more often in women with three or more births than in nulliparous women, incidence odds ratio, IOR 2.0 (95% confidence interval, CI: 1.0 3.9). Subjects who consumed alcohol weekly had a higher incidence of varicose veins compared to non-users, IOR 1.5 (95% CI: 1.05 2.3). The result was statistically significant only in women. Compared to non-smokers, subjects who had ever smoked for over a year, and of these heavier smokers (≥15 cigarettes a day), had higher risk of varicose veins, IORs 1.3 (95% CI: 0.9 1.8) and 1.8 (95% CI: 1.1 2.8) respectively. Daily use of meat seemed to decrease the risk of varicose veins compared to infrequent use (0 2 meals a week) of meat, particularly in women. Dietary fiber intake, use of contraceptive pills or hormone replacement therapy did not have an effect on the incidence of varicose veins.

In those with a positive family history of varicose veins the risk of varicose veins was increased compared to those with negative family history, IOR 1.6 (95% CI: 1.1 2.3). When genders were studied separately, the higher risk was statistically significant only in women, IOR 1.8 (95% CI: 1.1 2.8), but not in men, IOR 1.4 (95% CI: 0.7 2.6). The estimates of the risk were much lower than our prevalence results (OR 6.6 in men and OR 4.9 in women, respectively) and also those usually reported in the literature based on cross-sectional studies with prevalence estimates.

Subject s own varicose vein status or change in it was associated with self-reported family history of varicose veins. For example, if a person who at entry reported negative family history developed varicose veins during follow-up, the risk of reporting a family member with varicose veins after the follow-up was sixfold, OR 6.0 (95% CI: 2.0 47.8). If another person reported varicose veins at entry and at the end of the follow-up, the risk of reporting a new family member with varicose veins was less than 1 (OR 0.8 (95% CI: 0.6 0.9)).

In conclusion, in women, multiparity, alcohol consumption and positive family history of varicose veins increase the risk of varicose veins, whereas meals containing meat may reduce the risk. Smoking is likely a risk factor of varicose veins in both genders. The strong effect of family history on the risk of varicose veins in the literature is affected by differential misclassification bias.