Body mass index, abdominal fatness, weight gain and the risk of psoriasis: a systematic review and dose–response meta-analysis of prospective studies
European Journal of Epidemiology
https://doi.org/10.1007/s10654
Body mass index, abdominal fatness, weight gain and the risk of psoriasis: a systematic review and dose-response meta-analysis of prospective studies
Dagfinn Aune 0 1 2 3 4 5
Ingrid Snekvik 0 1 2 3 4 5
Sabrina Schlesinger 0 1 2 3 4 5
Teresa Norat 0 1 2 3 4 5
Elio Riboli 0 1 2 3 4 5
Lars J. Vatten 0 1 2 3 4 5
0 Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital , Oslo , Norway
1 Department of Nutrition, Bjørknes University College , Oslo , Norway
2 & Dagfinn Aune
3 German Diabetes Center (DDZ), Institute for Biometrics and Epidemiology, Heinrich Heine University Du ̈sseldorf , Du ̈sseldorf , Germany
4 Department of Dermatology, St. Olavs Hospital, Trondheim University Hospital , Trondheim , Norway
5 Department of Public Health and Nursing, Faculty of Medicine, Norwegian University of Science and Technology , Trondheim , Norway
Greater body mass index (BMI) has been associated with increased risk of psoriasis in case-control and cross-sectional studies, however, the evidence from prospective studies has been limited. We conducted a systematic review and doseresponse meta-analysis of different adiposity measures and the risk of psoriasis to provide a more robust summary of the evidence based on data from prospective studies. PubMed and Embase databases were searched for relevant studies up to August 8th 2017. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random effects model. The summary relative risk (RR) for a 5 unit increment in BMI was 1.19 (95% CI 1.10-1.28, I2 = 83%, n = 7). The association appeared to be stronger at higher compared to lower levels of BMI, pnonlinearity \ 0.0001, and the lowest risk was observed at a BMI around 20. The summary RR was 1.24 (95% CI 1.17-1.31, I2 = 0%, pheterogeneity = 0.72, n = 3) per 10 cm increase in waist circumference, 1.37 (95% CI 1.23-1.53, I2 = 0%, pheterogeneity = 0.93, n = 3) per 0.1 unit increase in waist-to-hip ratio, and 1.11 (95% CI 1.07-1.16, I2 = 47%, pheterogeneity = 0.15, n = 3) per 5 kg of weight gain. Adiposity as measured by BMI, waist circumference, waist-to-hip ratio, and weight gain is associated with increased risk of psoriasis.
Body mass index; Meta-analysis
Waist circumference
Waist-to-hip ratio Weight gain Psoriasis Systematic review Keywords Body mass index Meta-analysis
Introduction
Department of Epidemiology and Biostatistics, School of
Public Health, Imperial College London, St. Mary’s Campus,
Norfolk Place, Paddington, London W2 1PG, UK
Psoriasis is a chronic immune-mediated inflammatory skin
disease which is characterized by patches of abnormal skin,
which typically are red, itchy and scaly [
1
]. The condition
affects approximately 2% of the general population,
however, the prevalence has doubled over the recent decades in
some countries, reaching a lifetime prevalence of 5.8–11%
in Scandinavia [
2, 3
]. A diagnosis of psoriasis has been
associated with increased risk of coronary heart disease
[
4, 5
], atrial fibrillation [
6
], stroke [
5–7
], thromboembolism
[
7
], certain cancers [
8
], and possibly other conditions
[
9–13
]. Although several risk factors for psoriasis have
been suggested or established including age [
14
], family
history of psoriasis [
15, 16
], skin infections and skin
disorders [17], gallstones [
18
], smoking [
19
], alcohol
consumption [
20
], and physical inactivity [
21, 22
], much
remains to be learned.
Adiposity is associated with low-grade inflammation
through overproduction of inflammatory cytokines.
Activated macrophages in adipose tissue stimulate
adipocytes to secrete TNF-a, IL-1, IL-6, and IL-8, which may
contribute to the development of psoriasis [
23, 24
]. In
addition, higher levels of leptin, an adipokine related to
obesity, has also been associated with increased risk of
psoriasis [
25–27
]. A large number of cross-sectional and
case–control studies have reported a positive association
between adiposity and the risk of psoriasis [
28–42
]. A
meta-analysis from 2012 also suggested a positive
association between obesity (BMI of C 30 kg/m2) and psoriasis
[43], however, it was largely based on cross-sectional and
case–control studies, study designs which can be difficult
to rely on for causal inferences because (1) the temporality
of the association between the exposure and the disease is
not clear in cross-sectional studies, and (2) because case–
control studies may be hampered by recall and selection
biases. However, recently several prospective studies have
also reported on the association between body mass index
(BMI, kg/m2), abdominal fatness (waist circumference or
waist-to-hip ratio) or weight changes and the risk of
psoriasis [
17, 44–49
]. A large study from the UK found a 33%
increase in the risk of psoriasis among obese participants
compared to normal weight (BMI of 18.5 to \ 25.0 kg/
m2) participants (...truncated)