A systematic review was conducted on epidemiology studies on acne obtained from a Web of Science search to study risk factors associated with acne presentation and severity. A strong association was observed between several risk factors -family history, age, BMi and skin type -and acne presentation or severity in multiple studies. The pooled odds ratio of 2.36 (95% CI 1.97-2.83) for overweight/obese BMI with reference to normal/underweight BMI and the pooled odds ratio of 2.91 (95% CI 2.58-3.28) for family history in parents with reference to no family history in parents demonstrate this strong association. In addition, a pooled odds ratio of 1.07 (95% CI 0.42-2.71) was obtained for sex (males with reference to females). However, the association between other factors, such as dietary factors and smoking, and acne presentation or severity was less clear, with inconsistent results between studies. Thus, further research is required to understand how these factors may influence the development and severity of acne. This study summarizes the potential factors that may affect the risk of acne presentation or severe acne and can help researchers and clinicians to understand the epidemiology of acne and severe acne. Furthermore, the findings can direct future acne research, with the hope of gaining insight into the pathophysiology of acne so as to develop effective acne treatments. Acne epidemiologyThe Global Burden of Disease Study 2010 found that acne vulgaris (henceforth acne) is the eight most common skin disease, with an estimated global prevalence (for all ages) of 9.38% 1 . In different countries and among different age groups, the prevalence of acne varies, with estimates ranging from 35% to close to 100% of adolescents having acne at some point 2 . Symptoms and impacts of AcneAcne patients typically present with comedones, papules and pustules 3 . Comedones can be subdivided into two types -open comedones (blackheads), which are clogged follicles with openings exposing its contents to the air, and closed comedones (white heads), which are clogged follicles without an opening 4 . Papules are raised lesions on the skin that are smaller than 1 cm in diameter while pustules are similar to papules but inflamed and filled with pus 4 . In patients with severe acne, nodules and cysts -inflamed, swollen lesions that are at least 5 mm large -may be present 3,4 . In addition, other symptoms such as the scars, erythema and hyperpigmentation may be observed in acne patients 4 .On top of discomfort due to the clinical symptoms of acne, patients may experience other negative impacts. A study observed significantly higher unemployment rates among acne cases relative to controls, suggesting a correlation between acne and employment 5 . Further, acne has been found to adversely affect the social life 6 , self-esteem and body image of individuals and is often co-morbid with psychological disorders including depression and anxiety 3 . Additionally, acne is associated with substantial financial costs, with one study estimating that...

Background Multiple factors have been attributed to acne vulgaris predisposition and individual variations in the severity of skin symptoms, and genetics stood out as one of the major factors. Methods We performed a systematic review on the genes and their variants that have been investigated for association with acne presentation and severity. A random-effect meta-analysis using the allele model (minor allele vs. major allele) was also conducted to provide an overall estimation of risk effects of frequently reported gene variants. This included a subset data of 982 acne cases and 846 controls extracted from our existing GWAS database on various allergic and skin diseases among Singapore Chinese. Results Systematic review of 51 articles covering Asians and Caucasians found 60 genes/loci and their 100 variants implicated in acne; majority of them were in the intron, coding region/missense, and promoter regions. The commonly studied candidate genes/gene families include tumor necrosis factor (TNF), and the interleukin (IL) and cytochrome P450 (CYP) gene families. Our meta-analysis showed that most of the analyzed gene variants exhibited insignificant pooled odds ratio (pOR) and significant heterogeneity between studies. Nevertheless, we found that TNF rs1800629 A allele carriers and CYP17A1 rs743572 T allele carriers had significantly reduced mild acne risk [pOR: 0.60; 95% Confidence Interval (CI): 0.33–0.86] and severe acne risk (pOR: 0.59; 95% CI: 0.40–0.79), respectively, across populations. Overall, FST (follistatin) rs629725 A allele poses a significantly modest increased risk for acne presentation (pOR: 1.19, 95% CI: 1.14, 1.23), but neither TIMP2 (TIMP metallopeptidase inhibitor 2) rs8179090 nor CYP1A1 rs4646903 (pOR: 0.96, 95% CI: 0.80–1.12; pOR: 0.95, 95% CI: 0.83, 1.08), respectively. We discovered 15 novel SNPs in the 3′ UTR region of the Toll-like Receptor 4 gene (TLR4) associated with acne presentation. Conclusions This systematic review and meta-analysis suggest that genes influencing inflammatory responses, specifically TNF, and genes influencing the function and activity of sebaceous glands, specifically CYP17A1 and FST, have potential risk variants for acne presentation and severity across populations. Understanding the genetic susceptibility factors and biological pathways involved in the pathogenesis of acne will help us to gain insights into developing effective acne treatments.

<b><i>Background:</i></b> Acne vulgaris is classified based on the severity of skin lesions and post-healing scar types of these lesions. Numerous epidemiology studies have investigated the risk factors associated with acne presentation and severity, but studies for acne scarring are lacking. <b><i>Objective:</i></b> To investigate the prevalence of acne, severity, and scarring grades and their associated risk factors among Singapore Chinese. <b><i>Methods:</i></b> A total of 3,888 subjects (2,090 cases/1,798 controls; median age = 21 ± 4.589; range 17–71) completed an investigator-administered questionnaire as part of a cross-sectional study, which included sociodemographics, familial medical history, lifestyle factors, dietary habits, and acne history. Acne cases were further evaluated for their severity (<i>n</i> = 991) and scarring (<i>n</i> = 988) grades by a trained personnel. <b><i>Results:</i></b> The majority of the acne cases had mild acne/grade 1 scarring, while less than 1% had severe acne/grade 4 scarring. Parental acne was significantly associated with acne presentation and moderate/severe acne, while sibling acne was significantly associated with grade 3/4 scarring. Gender and age affected acne severity and scarring but not acne presentation, while tertiary maternal education level and the possession of ≥3 siblings were particularly associated with acne scarring. Underweight BMI was protective against acne presentation, while atopic diseases (asthma, allergic rhinitis, eczema) were its predisposing factors. Of the evaluated lifestyle factors, computer/TV usage had significant association with acne presentation, while alcohol consumption was significantly associated with acne severity. Frequent milk consumption was associated with a protective effect for moderate-severe acne, while frequent butter consumption had a detrimental effect on acne scarring extent. <b><i>Conclusion:</i></b> Positive familial history is a strong predisposing factor in determining acne presentation, severity, and scarring. Demographic factors (gender, age) and sedentary lifestyle (increased computer/TV usage) influence acne presentation, while dietary habits (milk and butter consumption) influence acne severity and scarring. The predisposing factors revealed in this study could help us to gain insights into acne pathophysiology and hence develop interventions especially targeting modifiable risk factors.

Background Acne vulgaris, a highly prevalent multifactorial inflammatory skin disease, can be categorised into different severity and scarring grades based on the type, number, and severity of lesions. While many epidemiology studies have investigated the risk factors for acne presentation, fewer studies have specifically studied the risk factors for acne severity and scarring. Therefore, this study investigated the prevalence of acne, acne severity and scarring grades, and their associated non-modifiable and modifiable epidemiological risk factors among Malaysian Chinese. Methods A total of 1840 subjects (1117 cases/723 controls) completed an investigator-administered questionnaire as part of a cross-sectional study, which include socio-demographics, familial history, lifestyle factors, dietary habits, and acne history. Acne cases were further evaluated for their severity (n = 1051) and scarring (n = 1052) grades by a trained personnel. Results Majority of the acne cases (up to 69%) had mild acne or Grade 1/2 scarring, while 21.6% had moderate/severe acne and 5.5% had Grade 3/4 scarring. Males had significantly higher risk of presenting with higher grades of acne scarring. Those who had acne, regardless of severity and scarring grades, had strong positive familial history (either in parents and/or sibling). Frequent consumption (most or all days) of foods that are commonly consumed during breakfast (butter, probiotic drinks, cereals and milk) decreased the risk for acne presentation and higher acne scarring, while periodic consumption (once/twice per week) of nuts and burgers/fast food decreased the risk for higher acne severity. Alcohol drinking was significantly associated with increased risk for acne presentation, while paternal, parental and household smoking were associated with reduced risk of more severe acne. Conclusions In conclusion, positive familial history is a strong predisposing factor in influencing acne presentation, severity and scarring. Frequent consumption of foods that are commonly consumed during breakfast is protective against acne presentation.

While the IGF1/FoxO1/mTORC1 signalling pathway is a well‐established nutrigenomic link between high glycaemic index (GI)/glycaemic load (GL) diet and acne vulgaris, other signalling pathways remain elusive. Therefore, we aimed to investigate other genes that are involved in the high GI/GL diet‐acne link, using our Singapore/Malaysia population epidemiological, genomics and transcriptomics data. High GI/GL dietary habit of 3207 acne cases (1869 and 1341 further classified into severity and scarring grades, respectively) and 2521 controls were evaluated based on Quality of Diet based on Glycaemic Index Score (QDGIS). Overlapping concordant differentially expressed genes (DEGs) between acne case–controls and QDGIS poor‐moderate/good classes were identified from whole‐transcriptome sequencing data of PBMC of a subset of participants. Finally, we assessed the expression quantitative trait loci (eQTL) association of single nucleotide polymorphisms (SNPs) of the concordant DEGs. Daily intake of fruits significantly reduced the risk of acne presentation, severity and scarring by up to 48.5%. Those with good QDGIS had significantly lower risk of mild and moderate/severe acne, and grade 1/2 acne scarring. Sequential filtering identified four overlapping concordant DEGs that were significantly associated with acne and QDGIS, namely GOLGA7B, SNCB, LOC102723849 and LOC283683. Combining transcriptome and genetic association data, we identified intronic SNP rs1953947 in GOLGA7B as an eQTL for acne. In conclusion, we identified GOLGA7B as a plausible novel gene that links high GI/GL with acne, and hence propose a model for the involvement of Golga7b in high GI/GL diet‐acne pathogenesis, which includes palmitoyl acyltransferase zDHHC5, fatty acid translocase CD36 and palmitic acid.