2037 - Risk Factors for Incident Gout Among Women: A Prospective Study

Wednesday, October 21, 2009: 12:00 PM
203 B (Pennsylvania Convention Center)
Vidula Bhole1, Mary De Vera1, M. Mushfiqur Rahman1, E. Krishnan2 and Hyon K. Choi3, 1Arthritis Research Centre of Canada, Vancouver, BC, 2Stanford University School of Medicine, Palo Alto, CA, 3Boston University School of Medicine, Boston, MA
Presentation Number: 2037

Purpose Despite recent doubling of the incidence of gout among women and substantial prevalence particularly in the aging female population, little data are available on the risk factors for gout among women.  Given the important gender differences in uric acid metabolism, role of sex hormones, and frequency of gout, the risk factors for gout may vary considerably between genders. We examined the relation between serum uric acid level, purported risk factors and the risk of incident gout among women in the Framingham Heart Study (FHS) cohort.

Methods Using data from FHS (1950-2002), we prospectively examined the relation between uric acid, purported risk factors and incidence of gout in 2,476 women and 1,951 men. We calculated the incidence rates of gout according to uric acid categories. We used Cox proportional hazards model with time-dependent variables to estimate the relative risk (RR) for incident gout by age, education, obesity, hypertension, diuretic use, alcohol use, glucose and cholesterol level, and menopausal status. We explored potential interaction by gender by testing significance of interaction terms added to our final multivariate models.

Results At baseline mean age of the cohort was 47 years and 50% women were postmenopausal. Mean baseline uric acid level was 4.5 mg/dL for the cohort; and 4.0 mg/dL for women. The proportion of individuals with obesity, hypertension, diuretic use, and heavy alcohol use were 13%, 13%, 4% and 14% respectively; and for women 14%, 15%, 6%, and 6%, respectively. Over 28 year median follow-up, we documented 304 incident gout cases, 104 in women. Incidence rates of gout for women per 1000 person years for uric acid levels of <5.0, 5.0-5.9, 6.0-6.9, 7.0-7.9 and ≥8.0 mg/dL were 0.8, 2.5, 4.2, 13.1, and 27.3, respectively (p for trend <0.0001). The magnitude of this association was significantly lower than that among men (p for interaction, 0.0002). The associations of purported risk factors and incident gout were similar between genders (Table), except for a stronger age effect among women (p for interaction, 0.02)

Multivariate RR

Women

Men

Age, per 5 yr

1.24 (1.08, 1.43)

1.14 (1.03, 1.26)

BMI, kg/m2

      <25

1.0

1.0

      25-30

1.44 (0.88, 2.37)

1.76 (1.22, 2.54)

      ≥30

2.74 (1.65, 4.58)

2.90 (1.89, 4.44)

Diuretics

       No

1.0

1.0

       Yes

2.39 (1.53, 3.74)

3.41 (2.38, 4.89)

Alcohol

      Light

1.0

1.0

      Moderate

1.30 (0.80, 2.12)

1.44 (0.99, 2.08)

      Heavy

3.10 (1.69, 5.68)

2.21 (1.56, 3.14)

Hypertension

      No

1.0

1.0

      Yes

1.82 (1.06, 3.14)

1.59 (1.12, 2.24)

Glucose, per 10 mg/dL

1.02 (0.98, 1.07)

0.99 (0.95, 1.03)

Cholesterol, per 10 mg/dL

0.99 (0.95, 1.04)

1.03 (0.99, 1.06)

Education, grades

      <12

1.0

1.0

      12

1.05 (0.67, 1.66)

0.86 (0.59, 1.24)

       >12

0.58 (0.34, 1.02)

1.12 (0.81, 1.56)

Menopause

       No

1.0

-

       Yes

3.54 (0.46, 27.15)

-

Conclusion Higher levels of serum uric acid increase the risk of gout in a graded manner among women, but the rate of increase is lower than that among men. The latter finding appears to provide another reason behind the lower background incident rates of gout among women that goes beyond their lower baseline serum uric acid levels. Age, obesity, hypertension, alcohol consumption, and diuretic use were associated with the risk of incident gout among women.   

Keywords: gout

Disclosure: V. Bhole, None; M. De Vera, None; M. M. Rahman, None; E. Krishnan, Savient, 1, Takeda, 2 ; H. K. Choi, None.