Epidemiologic determinants of skin photoaging: Baseline data of the SU.VI.MAX-cohort

Background: Although skin disorders associated with long-term sun exposure account for high morbidity, only few data on sun-related preclinical skin c hanges are available in the general population. Objective: In the present study we determined reference values for markers of photoaging in French adults, and we evaluated the relationship between p hotoaging, phototype, and both behavioral and environmental factors. Methods: The SU.VI.MAX trial is a multicenter, national intervention trial on 12,735 adults living in France. A transverse analysis was performed on t he inclusion data of the sample of volunteers between 45 and 60 years of ag e who underwent skin evaluation in 1995: 3057 women and 3606 men. Skin was evaluated by means of the Larnier skin photoaging photographic scale and a sun reactive skin type classification derived from those proposed by Fitzpa trick in 1976 and Cesarini in 1977. Results: The prevalence of skin photoaging, assessed as a dichotomous varia ble (from moderate/severe to very severe), was comparable in men and women in same age groups: in women, age group 45-49 years = 22%, 50-54 years = 36 %, and 55-60 years = 42%; in men, age group 45-49 years = 17%, 50-54 years = 38%, and 55-60 pears = 45%. After adjusting for body mass index, exposure to tobacco, and sunlight exposure, the only variables found to be related to skin photoaging in women were age (55-60 years age group: adjusted odds ratio [AOR] = 6.0, 95% confidence interval [CI] = 4.4-8.2), phototype IIIa, IIIb, and IV (AOR = 0.2, 95% CI = 0.1-0.4; AOR = 0.3, 95% CI = 0.2-6.6; an d AOR = 0.4, 35% CI = 0.3-0.8; respectively), menopausal status (AOR = 1.4, 95% CI = 1.1-1.9), and geographic location (Southern France: AOR = 0.7, 95 % CI = 0.6-0.9), with a more pronounced effect in lighter phototypes I-II a nd a protective impact related to southern locations. No relationship was f ound between the use of oral contraceptives and skin photoaging. The age ef fect was also found in men (55-60 years age group: AOR = 10.4, 95% CI = 8.3 -13.1) and geographic location (Southern France: AOR = 0.8, 35% CI = 0.6-0. 3), with a most pronounced effect in darker phototypes (phototypes > IV:AOR = 2.8, 95% CI = 1.4-5.6). Conclusion: Our results suggest-that the prevalence of skin photoaging in t he adult French population is determined by age, sex, geographic location, and phototype. The continuation of this longitudinal study will allow for t he investigation of the relationship between skin photoaging and the risk o f the development of skin diseases.