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Table 1 Prevalence of Varicose Veins in Adult Males and Females in Selected Epidemiological Surveys
Year Country Population Definition used n Female (%) Male (%)
1966 Wales (1) Population sample All varicosities 289 53.1 37.2
1969 Egypt (2) Cotton mill workers Excl. tel 467 5.8 –
1969 England (2) Cotton mill workers Excl. tel 504 31.1 –
1972 India (South) (3) Railway sweepers
All varicosities 323 – 25.1
1972 India (North) (3) Railway sweepers
All varicosities 354 – 6.8
1973 Switzerland (4) Chemical industry employees All varicosities 4529 55.0 56.0
1973 Switzerland (5) Shop and factory employees Excl. tel 610 29.0 –
1973 United States (6) Population sample All varicosities 6389 25.9 12.9
1974 Switzerland (7) Chemical industry employees All varicosities 4376 68.0 57.0
1975 New Guinca (9) Villagers All varicosities 1457 0.1 5.1
1976 New Zealand (8) General population All varicosities 356 37.8 19.6
1977 Tanzania (10) Outpatients All varicosities 1000 5.0 6.1
1981 Israel (11) Population sample Excl. small varicosities 4888 29.3 10.4
1986 Brazil (12) Health center patients Excl. tel. and retics 1755 50.9 37.9
1988 Sicily (13) Villagers All varicosities 1122 46.2 19.3
1990 Japan (14) Patients, hospital staff, elderly residents All varicosities 541 45.0 –
1991 Czechoslovakia (15) Shop employees All varicosities 696 60.5 –
1994 Turkey (16) General population All varicosities 850 38.3 34.5
1995 Scotland (17) General population Trunk varicosities 1566 32.2 39.7
1995 Finland (18) General population Varicose veins 7217 24.6 6.8
1998 Italy (19) General population All varicosities 1319 35.2 17.0
2000 United States (20) University employees Trunk varicosities 600 33.0 17.3
Abbreviations: Excl, excluding; tel, telangiectasia; retics, reticular veins.
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difference was found, but neither of these were large studies based on random samples of
the general population. On the other hand, males were found to have a higher prevalence in
New Guinea (9), Kenya (22) and Hong Kong (23). It has been suggested that the
prevalence rises first in males in developing countries due to their earlier contact with
Western culture, although this is purely hypothetical. However, in the Edinburgh Vein
Study a slightly higher prevalence was found in men (17), and this was also noted in young
adults in the Bochum Study in Germany (24). These are recent studies and there is a
possibility that the prevalence of varicose veins may be increasing in men. Also, the higher
prevalence in women in some studies may be due partly to recruitment bias because
relatively more women concerned about the cosmetic appearance of their varicosities may
volunteer to take part.
A common finding in epidemiological studies is that the prevalence of varicose
veins increases with age. For example, Table 2 shows that in men in the Edinburgh Vein
Study (17) prevalence increased from around 16% in those aged 25–34 years to 61% in
those 55–64 years. For women aged 25–34 years, prevalence was 14% rising to 51%
in those 55–64 years of age. In the Bochum Study, examination of schoolchildren aged
10–12 years demonstrated the presence of only discrete reticular varices in 10% of the
pupils, but four years later this figure had increased to 30%, and a few children had
developed stem and branch varices (25).
The prevalences of different categories of varicose veins (trunk, reticular, etc.) in
populations are difficult to determine because most studies do not provide such
information, and the classification of the categories and their severity varies between
USA (6)
New Zealand (8)
40
35
30
25
20
15
10
5
Israel (11)
Prevalence %
Turkey (16)
Scotland (17)
Finland (18)
Italy (19)
Figure 1 Prevalence of varicose veins in females in general population surveys.
Table 2 Prevalence of Varicose Veins by Age and Sex in Edinburgh Vein Study
% Varicose Veins (n)
Age (years) Men Women
18–24 20 (11) 5 (4)
25–34 16 (16) 14 (22)
35–44 36 (57) 23 (42)
45–54 42 (76) 42 (95)
55–64 61 (124) 51 (111)
Note: Varicose veins comprise only trunk varices of any grade of severity.
Source: From Ref. 15.
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studies. In the Basle Study (Survey II), 5.2% of men and 3.2% of women were considered
to have trunk varices, and 51.8% of men and 64.8% of women to have reticular varices
and/or telangiectasia (7). On the other hand, in the Basle Study (Survey III), the prevalence
of trunk varices in men had risen to 20% and in women to 16% (4). Such differences would
however be affected by variation in the age of subjects between the two surveys. By
comparison, a survey in Japan on highly selected groups of women found that 10% had
trunk varices, 16% had isolated non-trunk varices, 13% had reticular varices and 7% had
telangiectasia (14). In the Edinburgh Vein Study both reticular varices and telangiectasia
were found in over 80% of subjects although most were relatively mild. Clearly, more
information is required on the relative distributions of different categories of varices.
During the early 1970s, several authors produced anecdotal evidence derived from
clinical observations in developing countries, suggesting that varicose veins were rare in
Africa and other developing countries in comparison to the West (26). Some believed
that there was an equal prevalence throughout the world but the occurrence of fewer
complications in tropical Africa resulted in the condition presenting very rarely (27).
Meaningful comparisons between countries, however, can only be made if studies use the
same methods and are based on population surveys. In this regard, a study investigating
varicose veins in New Zealand and the South Pacific is of interest because any
differences were more likely to be real than to be due to methodological biases (8,21).
A marked difference in prevalence was found between the populations; for example, 44%
of New Zealand Maori women had varicose veins compared to less than 5% of Atoll
islanders. Furthermore, the prevalence among the New Zealand Maoris was similar to
that of New Zealand caucasians. More recently in Southern California, no differences
were found in the prevalence of trunk varices between Caucasian, Hispanic, Black and
Asian Americans (20).
Although there have been many studies examining the prevalence of varicose veins,
very little data is available on the incidence, that is, the rate of development of new cases.
In the Framingham Study (28) the annual incidence was found to be 1.9% per annum in
men and 2.6% in women. Interestingly, the incidence did not increase with age (Fig. 2) so
that the observed increase in the prevalence of varicose veins would therefore appear to be
a result of the relatively constant development of cases as people grow older. Thus,
increasing age per se would not appear to be a risk factor for the development of
varicose veins.
ASYMPTOMATIC VENOUS VALVE INCOMPETENCE: PREVALENCE
In recent years, the availability of duplex scanning has permitted vein reflux to be
measured non-invasively in epidemiological studies. In the Edinburgh Vein Study, for
example, duplex scanning was carried out on a random sample of men and women in the
general population aged 18 to 64 years. In individuals who had no evidence on clinical
observation of significant venous disease (other than minor telangiectasia or reticular
varicosities) around 35% had significant reflux (R0.5 sec) in at least one of eight venous
segments measured in each leg (29). Thus venous insufficiency in the legs may occur with
no evidence of varicose veins or other clinical manifestation.
Indeed, the Bochum studies in Germany have demonstrated that in the teenage years
venous reflux occurs much more commonly than clinical varicosities and that
asymptomatic reflux may be a normal precursor of clinical disease (24). For example,
among 14–16 years olds examined in Bochum Study II, 12.3% had saphenous reflux but
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only 1.7% had trunk varices, 0.8% had tributary varices and 4.1% incompetent perforators.
Four years later, nearly 20% had saphenous reflux with only 3.3% having trunk varices.
RISK FACTORS FOR VARICOSE VEINS
Numerous genetic, lifestyle, and physiological characteristics have been put forward as
possible risk factors for the development of varicose veins. Many of these factors, such as
low fibre diet and lack of exercise, are associated with “westernization” and have been
suggested as possible explanations for the apparent geographical variation in the
prevalence of varicose veins. However, the evidence linking most of these factors to the
development of varicose veins is extremely limited, particularly as there have been very
few properly conducted epidemiological studies. Table 3 summarizes the levels of
evidence available on possible risk factors for varicose veins.
Obesity
Obesity is commonly believed to be important in predisposing individuals to increased risk
of varicose veins. In a large case control study with over 500 subjects in each group (30),
40-49 50-59 60-69 70-79 80-89
0
1
2
3
4
5
6
7
8
9
10
A
g
e (years)
Females
Males
Incidence %
Figure 2 Annual incidence of varicose veins in males and females in the Framingham Study, United
States. Source: Adapted from Ref. 28.
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obesity, defined as O20% over ideal weight, was much more common in those with
trunk varicosities and telangiectasia than in controls (15% vs. 3%, p!0.0001). Similarly,
in the BasleStudy of chemical workers inwhich the results were age-adjusted,varicose veins
were more common in overweight women. But, in men, only telangiectasia and reticular
varicosities, and not trunk varices, were more common in overweight individuals (4).
Population-based studies have also shown a relationship between body mass and
varicose veins. In the community survey in West Jerusalem, people with varicose veins
had a higher body mass index (kg/m
2
) than normal (11). In multivariate analyses including
weight and height, weight remained significantly related to the occurrence of varicose
veins in women, but not in men. Similarly among caucasian New Zealanders, body mass
index was related to severity of varicose veins only in women and independently of parity
(8). In the Framingham Study, the incidence of varicose veins over a 16-year follow up
period was higher in subjects with a baseline body mass index of over 27 kg/m. On
multivariate analysis the difference was maintained in women, but not in men (28).
Likewise, in another longitudinal population study in the Netherlands, the incidence of
varicose veins in overweight women was higher than in those of normal weight at all ages
(31) but no increased risk was found in men.
Thus, the balance of evidence would suggest that a high body mass index is related
to the occurrence of varicose veins, but the evidence is much more convincing for women
than for men. It is also not clear whether the risk increases above a certain cut-off point or
is apparent across the range of body mass index.
Pregnancy
It is a widely held view that in many women, varicose veins appear for the first time during
pregnancy. However, pregnancy may merely be an exacerbating factor in those already
predisposed, rather than a primary cause (32). Epidemiological studies have sought to
determine whether a previous history of pregnancy or the number of pregnancies are
related to the occurrence of varicose veins. In the population based study in New Zealand,
Table 3 Risk Factors Implicated in the Etiology of Varicose Veins by Level of Research Evidence
Good evidence
Female
Obesity (only in women)
Number of pregnancies
Limited evidence
Inherited factors
Prolonged standing and sitting
Constipation
Poor evidence
Low dietary fiber
Tight undergarments
Oral contraceptive use
Hormone replacement therapy
No evidence
Smoking
Lack of exercise
Social class
The level of evidence relates to the demonstration of a positive association between the risk factor and occurrence
of varicose veins.
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a greater number of pregnancies in women of European origin was associated with an
increasing prevalence of varicose veins, and in Maoris with a greater severity of varicose
veins (8). The relationships between pregnancy and varicose veins was maintained on
adjustment for age, height and weight. In a study in a more selected population in Brazil
attending a health centre, a positive correlation was found between prevalence of varicose
veins and number of previous pregnancies, independently of age (12).
In the Basle Study (Survey III), age-adjusted rates of varicose veins were higher in
multiparous than primiparous women, who in turn had higher rates than nulliparae (4). The
Framingham Study is the one longitudinal study to relate the incidence of varicose veins to
various risk factors; it was found that the number of pregnancies was associated with
incidence, although the association was statistically nonsignificant (pO0.05) (28). The
only population-based study which has not found a relationship with number of
pregnancies was in Tecumseh, USA (6). In the above studies, associations were age
adjusted but not all were adjusted for obesity. Nevertheless, the balance of the evidence at
present would indicate that number of pregnancies is a risk factor for the development of
varicose veins. The precise relative risks are difficult to determine but results from the
Basle and Framingham Studies indicate that women with two or more pregnancies,
compared to those with a single pregnancy or no previous pregnancy, have an
approximately 20% to 30% increased risk of developing varicose veins (4,28).
It is not clear why pregnancy might increase the risk of developing varicose veins.
The common belief that pregnancy leads to varicose veins due to pressure of the pregnant
uterus obstructing venous return from the legs has been refuted, because the majority of
varices appear during the first three months of pregnancy when the uterus is not large
enough to cause mechanical obstruction. A hormonal factor or the additional burden of
increased circulating blood volume could be important.
Inherited Factors
Evidence on the role of genetic predisposition in the development of varicose veins is
limited and prone to considerable methodological difficulties. In one study investigating
the role of heredity in the etiology of varicose veins (33), the risk of varicose veins was
higher in those with affected relatives and if the relative was a male. However, such a study
relied on the patient’s history for the assessment of relatives, and this method has been
shown to be highly inaccurate (1). On the other hand Cornu-The
´
nard et al. clinically
examined the parents of 67 cases of varicose veins and 67 spouse controls (34). They
found that both the mothers and fathers of cases were more likely than parents of the
controls to have varicosities and a history of treatment (Table 4). In a study of several
hundred twins in Germany, (35) 76 pairs were found on examination to have varicose
veins in at least one twin. Of monozygous pairs, 42% both had primary varicose veins
compared to 11% of dizygous pairs (concordant quotient 4:1).
Thus, the few studies on heredity are inconclusive but indicate that genotype could
well have an important effect on the risk of acquiring varicose veins. A study on the
cadavers of black Africans showed that they have a higher number of valves than
Caucasians when comparing the same section of leg vein (36). This suggests that the
number of valves is an inherited factor differing between races and may account for the
differences in prevalence of varicose veins seen in different parts of the world. Clearly,
there is a need for substantial research on the genetics of varicose veins including family
studies of modes of inheritance, twin studies, and the investigation of certain genotypes,
such as collagen genes which may influence the structure and biochemical composition of
the vein wall.
Epidemiology of Venous Disorders 43
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Lifestyle Factors
Prolonged standing has often been blamed for the development of varicose veins. Standing
at work was shown to be positively associated with varicose veins in the study in Israel
(11). However among women in Czechoslovakia, an association with standing was found
only for varices of the main trunk veins (15). In the Framingham Study, the two-year
incidence of varicose veins was higher with the length of time women spent sitting or
standing (28) but no significant difference was found relating posture to varicose veins in a
study from Brazil (12). Comparing railway sweepers in north and south India, both groups
were engaged in the same job, and therefore posture at work could not account for the
observed difference in prevalence (3).
Sitting in a chair has also been implicated. This practice is a Western habit not
adopted by primitive communities in which prevalence of varicose veins is apparently
low. In New Guinea, varicose veins were common inmen who sat “with the legs dangling”,
but rare in women who sat cross-legged on the ground, suggesting that variation in sitting
positions might be the cause of this sex difference (9). Alexander proposed that sitting in a
chair increased the hydrostatic pressure exerted onthe leg veins, leading to pooling ofblood
in the legs, venous dilatation and increased tension in the wall itself (23). The effect of
chair-sitting during childhood could therefore produce veins of an increased calibre which
would be more susceptible to factors such as pregnancy, standing and tight clothes.
Tight undergarments may raise intra-abdominal pressure, and in theory might
promote the development of varicose veins. In cotton workers in England and Egypt in the
1960s, the prevalence of varicose veins increased with the tightness and stiffness of the
undergarment being worn (2). In Jerusalem, habitual corset-wearing was also a
positive risk factor, (11) but in Swiss women the association between corset-wearing
and varicose veins was lost on correcting for age (5).
A positive risk factor for the development of varicose veins in a study in Sicily was
constipation (13), but this was not important in the study of cotton workers (2). Such
results are however of dubious value because of the difficulty of measuring constipation in
a valid and reliable way. Among inhabitants of the South Pacific, the prevalence of
varicose veins was low in primitive peoples, but high in more westernized cultures where
the diet contained more refined carbohydrate and less dietary fiber (21). A typical low fibre
Western diet produces small, hard stools which are difficult to pass, leading to regular
straining and repeated increases in intra-abdominal pressure. In the Edinburgh Vein Study,
Table 4 Venous Status of Parents of Cases of Varicose Veins and Controls
% Mothers % Fathers
No. of Cases
(nZ67)
No. of Controls
(nZ67)
No. of Cases
(nZ67)
No. of Controls
(nZ67)
Varicose veins
Long saphenous 46.3 26.9 38.8 14.9
Short saphenous 32.8 16.4 23.9 4.5
Nonsaphenous 19.4 10.4 10.4 6.0
Telangiectasia 83.6 73.1 41.8 28.8
Varicose vein treatment
Surgery 28.4 6.0 19.4 0.0
Sclerotherapy 44.8 19.4 21.9 3.0
Source: From Ref. 34.
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straining in men was related to a higher risk of trunk varices (37). Cleave postulated that
during constipation, the loaded bowel compresses the iliac vein thus obstructing venous
return from the legs, ultimately leading to the development of varicose veins (38).
Alternatively, raised intra-abdominal pressure from straining at stool may be transmitted
down the veins of the legs, leading to dilation of the veins and non-apposition of the valve
cusps, thus rendering the valves incompetent.
Many other factors have been implicated in the development of varicose veins. These
include lack of exercise, cigarette smoking, and use of oral contraceptives. However, the
evidence linking these and most of the other factors above to the occurrence of varicose
veins is tenuous.The relationship between obesity, pregnancy and the occurrence of venous
insufficiency is the most convincing but for many factors, the relationship with varicose
veins may be related more to confounding by other factors than a direct causal association.
VENOUS SKIN CHANGES: PREVALENCE
The prevalence in the general population of skin changes due to venous insufficiency, such
as hyperpigmentation, eczema and edema, have not been well documented. In the
population study in Tecumseh, USA (6), 3.7% of women and 3.0% of men had evidence of
skin changes. The prevalence increased markedly with age so that, for example, in women,
only 1.8% of those aged 30–39 years had skin changes compared to 20.7% of those over
70 years of age. In the Basle Study (II), the prevalence of “pronounced” skin changes
(dilatation of subcutaneous veins, hyper- or hypo-pigmentation) was found in 9.6% of
women and 8.7% of the men (7). Mild skin changes in the form of a venous flare occurred
in 15% of women and 10% of men. These results were, however, based on active chemical
industry employees and not on the general population. Nevertheless, the results from both
the Basle and Tecumseh studies suggest that there is not such a large female to male
preponderance of skin changes as there is for varicose veins.
In surveys of individuals with varicose veins, a considerable proportion have
evidence of skin changes. For example, in a survey of varicose vein patients in Brazil (12),
edema was the commonest manifestation occurring in nearly 20% of subjects.
Hyperpigmentation occurred in 6% and eczema in 1–2%. The community-based study
in Tecumseh, USA found that 10% of men and 20% of women with varicose veins had
edema (6). In female cotton workers in the 1960s in England, 10% of women with varicose
veins had skin changes or ulceration (2), whereas only 2.5% of South India railworkers
with varicose veins had such signs (3). In the Basle Study, (Survey II), the prevalence and
severity of various grades of skin change was found to relate to the severity of varicose
veins (7). Among those with severe varicose veins (marked trunk varices), the prevalence
of skin changes or ulceration was 81% and among those with minor varicose veins
(reticular veins and/or telangiectasia or “scarcely visible trunk varices”) the prevalence
was 30%.
VENOUS ULCER: PREVALENCE, INCIDENCE, AND PROGNOSIS
The prevalence of chronic leg ulcers found in several epidemiological surveys (4,6,39–48)
in the general population is shown in Table 5. It is important to distinguish between the
occurrence of open (active) ulcers in the population and the combination of open and
healed ulcers because very different figures will prevail. The prevalences also vary greatly
because of the different sampling methods, ages of the populations, and definitions of
ulceration. Furthermore, some studies include all chronic ulcers whereas others include
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Table 5 Prevalence of Venous Ulcers in Adult Males and Females in Selected Epidemiological Surveys
Prevalence of ulcer
Year Location Survey method n Population Type of ulcer Male (%) Female (%)
1973 Tecumseh, USA (6) Examination 6389 General, 10 yrsC Venous, active or
healed
0.1 0.3
1978 Basle, Switzerland (4) Examination
4529 Chemical workers,
25 yrsC
Chronic, active or
healed
1.0 1.0
1985 Lothian/Forth Valley,
Scotland (41)
Health Service 1 million General, 20 yrsC Chronic active 0.15
1986 Ireland (41) Health Service 92,100 General, 40 yrsC Chronic active 0.38
1986 Harrow, England (40) Postal
2,012 General, all ages Chronic active 1.0 2.1
1991 Perth, Australia (42) Health Service 238,000 General, 20 yrsC Chronic active 0.11
1991 Skaraborg, Sweden (43) Health Service 270,800 General, all ages Chronic active 0.22 0.39
1992 Malmo, Sweden (44) Health Service
232,908 General, all ages Chronic active 0.12
1992 Newcastle, England (45) Health Service 107,400 General, 45 yrsC Chronic active 0.19
1993 Gothenburg, Sweden (46) Postal
5,140 General, 65 yrsC Chronic active 3.2 1.5
1996 Skovde, Sweden (47) Postal and examination
2785 Industrial workers,
30–65 yrs
Chronic, active or
healed
1.6
2000 Village, Sweden (48) Postal and examination
541 General, 70 yrsC Chronic, active or
healed
12.6
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only those believed to be primarily of venous origin. Reviewing the results overall, a very
approximate estimate of the prevalence of open venous ulceration in the adult population
over 18 years of age in Western countries is about 0.3%. That is, about one in 350 adults
are affected at any one time. For every patient with an open ulcer in the population, there
would appear to be between two and four individuals with healed ulcers, so that the
population prevalence of open and healed ulcers combined could be around 1% (43).
These summary figures are, however, very rough estimates.
In many of the epidemiological studies, the prevalence of ulceration is not given
separately for males and females. Table 5 shows that in the studies reviewed, three
studies found a female predominance of two to three times that in males, (6,41,43) one
found no difference, (4) and another a male predominance (46). However, other
epidemiological studies have found a female:male ratio ranging from approximately 2:1
to 3.5:1. Thus, overall it would appear that the prevalence of ulcers is around two to three
times more common in females than males. Chronic leg ulceration is relatively
uncommon below the age of 60 years (40). Above that, the prevalence increases
consistently with age in both men and women (39–43) with the female predominance
being maintained at all ages.
The prognosis of chronic venous ulcers is often poor. Typically, in patients attending
for treatment, only half the ulcers are healed within four months (49). Information on the
duration of ulcers existing in the general population at any point in time has been obtained
in prevalence surveys in which the duration of ulcers was assessed retrospectively
(44,45,50–52). The results of these studies were similar; for example, in the Lothian and
Forth Valley Leg Ulcer Study in Scotland, 20% of ulcers had not healed after two years,
and 8% had been open for five years. The longest duration was 62 years in an 85 years old
woman (51).
In a similar way the duration of the ulcer diathesis, i.e. the length of time in which
ulcer patients in a community have experienced ulcers irrespective of whether they were
consistently open, has been investigated retrospectively. In the Lothian and Forth Valley
Study, 45% had had episodes for more than 10 years and 21% for between five and
ten years. The number of episodes of active ulceration has also been recorded in some
surveys (50–52). Approximately one-third were shown to have had one episode and at
least another third were likely to have had four or more episodes. Although these figures
were based on all chronic leg ulcers, and not just venous ulcers, they do reflect the situation
for venous ulcers which comprise the majority of all leg ulcers.
Limited data is available on the incidence of development of new chronic ulcers in
the general population. In a retrospective survey in England, the annual incidence rate was
estimated to be 3.5 per 1000 in those aged over 45 years of age, (45) whereas in the
population over 15 years of age in Olmsted County, Minnesota, it was nearly two per
10,000 (53).
RISK FACTORS FOR VENOUS ULCERS
Venous ulcers are at the severe end of the spectrum of venous disease in the legs. It is not
surprising therefore that less severe forms of venous disease, such as varicose veins and
skin changes are associated with mild chronic venous disease, and increase the risk of the
development of varicose ulcers. In the Basle Study, for example, the risk of developing
varicose ulcers during an 11 years follow-up period was 0.8% for those with mild
varicosities but 20% for those with severe varicose veins (Fig. 3).
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