Oral acetylsalicylic acid and prevalence of actinic
               keratosis

A case-control study with dermatologic outpatients above 50 years of age assessed between 2009 and 2011. Cases were defined as those who had been under regular use of oral acetylsalicylic acid for more than six consecutive months. The assessment focused on: age, sex, skin-type, tobacco smoking, use of medication, occurrence of individual or family skin cancer, and sunscreen and sun exposure habits. Actinic keratoses were counted in the medial region of the face and upper limbs. Counts were adjusted by co-variables based on a generalized linear model.

Results:

A total of 74 cases and 216 controls were assessed. The median time of acetylsalicylic acid use was 36 months. Cases differed from controls as to the highest age, highest prevalence of use of angiotensin-converting enzyme inhibitors and fewer keratosis on the face and on the upper limbs (p<0.05). The multivariate model showed that the use of acetylsalicylic acid was associated to lower counts of face actinic keratosis and upper-limb erythematous actinic keratosis (p<0.05), regardless of other risk factors.

Conclusion:

The regular use of oral acetylsalicylic acid for more than six months was associated to a lower prevalence of actinic keratosis, especially facial and erythematous ones.

actinic keratosis; acetylsalicylic acid; prevalence; risk factors

Variables	Cases	Controls	OR (95% CI)	p^a a Unadjusted values;
Female sex - N(%)	47 (64)	149 (69)	0.78 (0.5-1.4)	0.39^b b Chi-square test;
Age - average (standard deviation)	63.5 (58-70)	59 (55-66)	-	0.00^c c t-student test;
Skin type - N(%)				0.41^d d Tendency chi-square;
I-II	20 (27)	44 (20)	1.40 (0.7-2.8)
III	30 (41)	98 (45)	0.94 (0.5-1.8)
IV	24 (32)	74 (34)	1.0
Sunburn history - N(%)	44 (59)	141 (65)	0.78 (0.5-1.3)	0.37^b b Chi-square test;
Personal history of skin cancer - N(%)	11 (15)	41 (19)	0.75 (0.4-1.5)	0.43^b b Chi-square test;
Family history of skin cancer - N(%)	11 (15)	28 (13)	1.17 (0.6-2.5)	0.68^b b Chi-square test;
Sun-exposed occupation (last 10 years) - N(%)	13 (18)	35 (16)	1.10 (0.6-2.2)	0.79^b b Chi-square test;
Sun-exposed leisure - N(%)	30 (41)	63 (29)	1.66 (1.0-2.9)	0.07^b b Chi-square test;
Daily use of sunscreen for more than 2 years - N(%)	10 (14)	46 (21)	0.58 (0.3-1.2)	0.14^b b Chi-square test;
Regular use of ACEI - N(%)	35 (47)	39 (18)	4.07 (2.3-7.2)	0.00^b b Chi-square test;
Smoking now - N(%)	10 (14)	41 (19)	0.67 (0.3-1.4)	0.29^b b Chi-square test;
Face AKs - Median (Q1-Q3)	1 (0-4)	3 (1-6)	-	0.02^e e Negative binomial regression
Erythematous face AKs	1 (0-4)	3 (1-5)	-	0.01^e e Negative binomial regression
Hypertrophic face AKs	0 (0-0)	0 (0-0)	-	0.59^e e Negative binomial regression
UL AKs (Q1-Q3)	0 (0-3)	1 (0-3)		0.03^e e Negative binomial regression
Erythematous UL AKs	0 (0-3)	1 (0-3)	-	0.02^e e Negative binomial regression
Hypertrophic UL AKs	0 (0-0)	0 (0-0)	-	0.72^e e Negative binomial regression

Variables	Face AKs				UL AKs
Variables	Erythematous		Hypertrophic		Erythematous		Hypertrophic
	estimator β	p	estimator β	p	estimator β	p	estimator β	p
Use of ASA	-0.8	0.00	-0.7	0.01	-0.3	0.03	-0.4	0.24
Age	0.1	0.00	0.1	0.00	0.1	0.00	0.1	0.00
Female gender	-0.2	0.11	-	-	-	-	-	-
Skin type		0.00		0.00		0.00		0.00
I-II	1.1		1.7		2.9		2.6
III	0.6		1.0		1.3		1.6
IV	0.0		0.0		0.0		0.0
Sunburn history	0.3	0.12	1.0	0.01	-	-	-	-
Personal history of skin cancer	^-	^-	0.7	0.16	0.3	0.10	0.5	0.15
Family history of skin cancer	0.3	0.25	^-	^-	0.7	0.00	0.8	0.10
Sun-exposed occupation (in the past 10 years)	-	-	-	-	0.4	0.09	0.8	0.03
Sun-exposed leisure	0.2	0.12	1.1	0.02	-	-	-	-
Regular use of ACEI	-	-	-	-	0.3	0.11	0.5	0.16
Daily use of sunscreen for more than 2 years	^-	^-	-1.9	0.08	-0.6	0.14	-1.1	0.05
Smoking now	-	-	-	-	0.9	0.00	1.4	0.00
Deviance (model)	216.7		91.0		336.2		145.8
p (model)	<0.01		<0.01		<0.01		<0.01

Associação Médica Brasileira R. São Carlos do Pinhal, 324, 01333-903 São Paulo SP - Brazil, Tel: +55 11 3178-6800, Fax: +55 11 3178-6816 - São Paulo - SP - Brazil
E-mail: ramb@amb.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] Correspondence: Departamento de Dermatologia, S/N, Faculdade de Medicina da UNESP, Campus Universitário de Rubião Jr., ZIP Code: 18618-970, Botucatu - SP - Brazil, Phone/Fax: +55 14 3880-1267. julivs@gmail.com