You are here

Article Text

Article menu
Dermatology
Original research
Prevalence and risk factors of senile pruritus: a systematic review and meta-analysis
  1. Shi Chen1,
  2. Faquan Zhou2,3,
  3. Yiquan Xiong4
  1. 1Institute for Disaster Management and Reconstruction of Sichuan University and Hong Kong Polytechnic University & West China School of Public Health, Sichuan University, Chengdu, China
  2. 2Department of General Surgery, The General Hospital of Western Theater Command, Chengdu, China
  3. 3North sichuan medical college, Nanchong, China
  4. 4Chinese Evidence-based Medicine Center, West China Hospital, Sichuan University, Chengdu, China
  1. Correspondence to Shi Chen, Institute for Disaster Management and Reconstruction of Sichuan University and Hong Kong Polytechnic University & West China School of Public Health, Sichuan University, Chengdu, China; 653645955{at}qq.com

Abstract

Objectives To systematically assess the prevalence and risk factors for senile pruritus (SP) in the elderly (≥60 years of age).

Design A meta-analysis was used to pool the prevalence and risk factors for SP estimated from individual studies. Four subgroup analyses were conducted to explore the prevalence for SP in different age, sex, research sites and region.

Setting, participants and measures SP reduces quality of life in the elderly, yet the worldwide prevalence is unclear. Moreover, the risk factors for SP are controversial. Data from cross-sectional studies, case–control studies, longitudinal studies and cohort studies that reported the prevalence or the risk factors for SP were collected by searching nine electronic databases up to October 2020, including Web of Science, PubMed, Embase, Cochrane Library, CINAHL, CBM, CNKI, Wanfang and VIP. Two reviewers independently screened studies according to the inclusion and exclusion criteria, extracted data and assessed methodological quality. Data analysis was performed using Stata V.15.1 software.

Results Seventeen studies involving 28 666 participants were included. The overall pooled prevalence of SP was 21.04% (95% CI 11.37% to 32.72%). In addition, the results showed that smoking, excessive drinking and monophagism were possible risk factors for SP, with pooled ORs of 1.26 (95% CI 1.14 to 1.40), 25.03 (95% CI 18.28 to 34.25) and 1.22 (95% CI 1.12 to 1.33), respectively.

Conclusions The overall prevalence of SP was high. Smoking, excessive drinking and monophagism were possible risk factors for SP.

PROSPERO registration number CRD42019143295.

  • geriatric dermatology
  • dermatological epidemiology
  • perinatology

Data availability statement

Data are available in a public, open access repository. All data relevant to the study are included in the article or uploaded as online supplemental information.

http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/bmjopen-2021-051694

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    Strengths and limitations of this study

    • To our knowledge, this study is the first systematic review and meta-analysis providing comprehensive assessment on the prevalence of senile pruritus (SP) in worldwide.

    • The risk factors of SPs are evaluated.

    • This systematic review and meta-analysis, covering five different countries, was composed of 17 studies, with 28 666 participants were included.

    • The definitions of SP differed across the included studies.

    Introduction

    The geriatric population (≥60 years of age) has been growing steadily worldwide in recent decades. It is estimated that the geriatric population will account for 20% of the world’s population by the middle of this century.1–3 Ageing results in numerous adverse changes in the structure and function of multiple human organs, including the skin.4 Senile pruritus (SP) is defined as generalised pruritus in patients without primary skin lesions.5–8 Pruritus is the most common skin disorder in the geriatric population.9 It can lead to an unpleasant cutaneous sensation, which provokes the desire to scratch (itchiness) and is accompanied by skin lesions, pain and infection.10 Furthermore, it can lead to adverse consequences for patients’ psychological health and quality of life, including anxiety, depression, disruption of normal sleep patterns and poor daytime concentration.10 11 Therefore, investigating the prevalence of SP is essential for informing policymakers, clinicians, and the general population.

    The prevalence of SP has been reported around the world, ranging from 41% in Thailand,12 40.6% in America,13 18.9% in Italy14 and 14.2% in China.15 However, these studies were limited by sample size and regional differences, and therefore do not represent the prevalence of SP worldwide. Furthermore, several studies conducted surveys on inpatients or outpatients to report the prevalence of SP.1 11 16 17 Inpatients or outpatients do not represent the whole elderly population, making the results less representative of the actual prevalence of SP in the community. For these reasons, the precise prevalence and characteristics of the population are unknown worldwide. Furthermore, the risk factors for SP have been reported extensively, but with controversial conclusions.18 19 For example, Yang et al indicated that smoking was associated with SP (OR 2.23, 95% CI 1.35 to 17.40).18 However, Chen et al reported that smoking was not associated with SP (OR 1.25, 95% CI 0.99 to 1.35).19

    In this study, we conducted a systematic review and meta-analysis to synthesise the prevalence of SP in different ages, sexes and regions based on the general population and to evaluate the risk factors for SP.

    Materials and methods

    Protocol registration

    This study was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.20

    Search strategy

    Nine databases were searched in this study, including Web of Science, PubMed, Embase, Cochrane Library, CINAHL, CBM, CNKI, Wanfang and VIP. The following strategy was used in the searches: (Pruritus OR Itching) AND (Senile OR Aging OR Aged OR Geriatrics) AND (Incidence OR Epidemiology OR Prevalence OR Risk factors). Complete details of the search strategy are available in online supplemental table S1. All of the databases were searched from their inception dates to the 24 October 2020. Additional relevant literature was included following a manual search of the included studies reference lists.

    Inclusion and exclusion criteria

    The inclusion criteria were as follows: (1) the study design was either cross-sectional study, case–control study, cohort study or longitudinal study; (2) participants were greater than or equal to 60 years of age; (3) exact diagnostic criteria for SP were provided and (4) prevalence or risk factors for SP were reported. The exclusion criteria were as follows: (1) the study populations were inpatients and outpatients; (2) the prevalence or risk factor effect value (mainly referred to as OR in this study) of SP was not clearly reported in the original study, and the data provided by the original study couldn't calculate the prevalence or risk factor effect value of SP; (3) republished literature and (4) or studies published in a language other than Chinese or English.

    Quality of the studies

    Two independent reviewers assessed the quality of the included studies according to 11 criteria recommended by the American Agency for Healthcare Research and Quality. The criteria included assessment of selection bias, performance bias, attrition bias, detection bias and publication bias. An item would be scored ‘1’ if it was answered ‘YES’, and if it was answered ‘NO’ or ‘UNCLEAR’, then the item scored ‘0’,21 providing a maximum score of 11.

    Data extraction

    Study selection and data extraction were independently conducted by two reviewers. Any disagreement was resolved by discussion the two reviewers or a third reviewer. The articles were first screened by the title and abstract, and then full-text documents were reviewed for inclusion if they reported the prevalence and risk factors for SP. By using a standardised and pilot-tested form, two reviewers independently extracted data from eligible studies, including the title, first author name, publication year, study location, age, sample size, diagnostic criteria, prevalence and risk factors for SP.

    Data analysis

    Double arcsine transformation was used to convert the prevalence of SP so that the data can follow an approximately normal distribution.22 The ORs with their corresponding 95% CIs were selected to assess the effect size of risk factors for SP. Heterogeneity among studies was tested by Cochrane’s Q and I2 statistics. Heterogeneity was recognised as significant when I2 >50%. A fixed-effect model (Mantel and Haenszel method) was used if I2 ≤50%, otherwise a random-effects model (DerSimonian and Laird method) was used.23 Forest plots were constructed for a visual display of the pooled results if necessary. Four subgroup analyses were conducted to explore the prevalence for SP in different age, sex, research sites and region. Sensitivity analysis were assessed by excluding single studies. Publication bias was assessed by using Begg’s and Egger’s tests.24 Tests of publication bias and sensitivity analysis were not conducted in the risk factor analysis section due to the limited number of studies included. Statistical analyses were conducted using STATA V.15.1 (Stata).

    Results

    Study description

    A total of 8518 records were identified from the 9 databases, of which 647 were duplicates. After screening titles and abstracts, 7740 records were excluded with reasons of age, outcome, study design. Full-text documents of 131 records were screened, and 114 studies were excluded with reasons listed as follows: participants were not ≥60 years of age (n=49), outcome was not SP (n=44), not cross-sectional, case–control, cohort or longitudinal study (n=9), non-Chinese and English study (n=5), duplicate publication (n=7). In summary, 17 studies were eligible and included in the meta-analysis finally (figure 1).

    Figure 1
    Figure 1

    Flow chart of the study selection process.

    Characteristics of the included studies

    The characteristics of the 17 studies are summarised in table 1. Eleven articles were written in Chinese,18 19 25–33 and six were written in English.34–39 Thirteen studies were conducted in Asia18 19 25–33 35 37 and four in Europe.34 36 38 39 Sample sizes ranged from 4539 to 8252.36 Four of the 17 studies reported the risk factors for SP.18 19 26 33

    View this table:
    Table 1

    Characteristics of included studies

    Risk of bias assessment

    Results of the risk of bias assessment are listed in online supplemental table S2. Higher scores indicative of less bias and more quality. Article quality was assessed as follows: 0–3 indicates a low quality, 4–7 indicates a moderate quality and 8–11 indicates a high quality.40 Study quality was found to be moderate in 11 studies and high in the other six studies.

    Prevalence of SP

    Seventeen studies, involving 28 666 participants reported the prevalence of SP, ranging from 5.63% to 66.91%. A random-effects model-based meta-analysis showed that the pooled prevalence of SP was 21.04% (95% CI 11.37% to 32.72%). Subgroup analyses indicated that the pooled prevalence of SP for people aged 60–69, 70–79, 80–89 and ≥90 years old were 11.98% (95% CI 3.91% to 23.62%), 26.79% (95% CI 8.71% to 50.36%), 51.31% (95% CI 47.20% to 96.33%) and 57.53% (95% CI 8.18% to n98.09%), respectively. The pooled prevalence of SP was 8.26% (95% CI 5.88% to 11.00%) in females and 18.65% (95% CI 0.83% to 51.61%) in males. The pooled prevalence of SP in health examination centres, nursing homes and communities was 43.83% (95% CI 19.39% to 69.94%), 16.26% (95% CI (4.55% to 33.29%) and 12.21% (95% CI 3.46% to 25.34%), respectively. The pooled prevalence of SP in Turkey and China was 24.34% (95% CI 14.03% to 36.38%). The pooled prevalence of SP in Norway, Denmark and Britain was 8.23% (95% CI 6.36% to 10.35%). The results of subgroup analyses of age, sex, research site and region are shown in table 2.

    View this table:
    Table 2

    Subgroup analyses by age, sex, research sites and region

    Risk factors

    Four studies, including 5619 participants, reported the risk factors for SP.18 19 26 33 There were three studies,18 19 33 including 4383 participants, that reported the association of smoking and SP. Meta-analyses showed smoking was associated with SP (pooled OR of 1.26 (95% CI 1.14 to 1.40), I2=0%). The results of two studies,19 33 involving 598 participants, suggested that excessive drinking increased the occurrence of SP (pooled OR of 25.03 (95% CI 18.28 to 34.25), I2=0%). Two studies19 33 involving 589 participants reported the association of monophagism and SP (pooled OR of 1.22 (95% CI 1.12 to 1.33), I2=0%) (table 3).

    View this table:
    Table 3

    Pooled risk factors of senile pruritus

    Sensitivity analysis

    Sensitivity analysis was performed by excluding a single study and showed that the results of the meta-analysis were stable (18.61%–22.23%). Sensitivity analysis was not conducted for the risk factor analysis due to the limited number of studies.

    Publication bias

    Publication bias was assessed by using Begg’s and Egger’s tests. Begg’s (Z=0.70, p=0.484) and Egger’s test (t=0.26, p=0.796) results showed that the possibility of publication bias was less in the overall prevalence pooled analysis. Publication bias was not assessed in the risk factor analysis due to the limited number of studies.

    Discussion

    In this study, 17 studies involving 28 666 participants were included encompassing Norway, China, Denmark, Turkey and Britain. Subgroup analyses found that the difference in the prevalence of SP based on epidemiological factors. Subgroup analyses indicated that a steadily increasing prevalence of SP was associated with increasing age. Xerosis is related to ageing and is reported as the most common cause of SP.41–43 One of the skin’s most important functions is to retain water. skin surface lipids and sebum on the skin helps retain water.44 As skin ages, there is a decrease in lipids and sebum on the skin, leading to suboptimal moisture retention.42 It was reported that pruritus can also be secondary to diabetes, kidney disease, liver disease, etc.44 45 Furthermore, pruritus is commonly listed as a medication complication,46 including ACE inhibitors, salicylates, chloroquine and calcium channel blockers.44 However, elderly people have more basic diseases and complex medication, which also contributed to the higher incidence of pruritus. Another view is that SP is probably a subclinical neuropathy, degenerative change in peripheral nerve endings may be attributable to age. This age alteration can cause pruritus without specific stimuli.7 In addition, immunosenescence occurs with ageing and also produces a higher incidence of pruritus.42 Moreover, decreases in androgen, oestrogen and glucocorticoid in aged people can contribute to SP.47 48 All these factors will increase the prevalence of SP with age.

    The results of subregional analyses found that individuals who were living in Turkey and China were associated with a higher prevalence of SP. Pruritus is influenced by multiple factors, such as genetic, biological, psychological, social, environmental and cultural factors.49 Different countries vary in society, culture and environment, genetic, biological and psychological factors also differ among populations in different countries. Therefore, the different prevalence among countries is related to the above factors.

    The results of subsex found that the prevalence of male is higher. Subresearch sites analyses found that the highest prevalence of SP was found in health examination centres. The reasons for these results are unclear based on the current scientific knowledge available on SP prevalence. Further studies would be helpful in further exploring these phenomena. In conclusion, the prevalence of SP varies among different populations. However, the reasons underlying the differences in prevalence observed in the current study remain unclear. It is suggested that further studies of the prevalence of SP in different populations be conducted in the future.

    Meta-analyses showed that smoking, excessive drinking,and monophagism were possible risk factors for SP. It has been shown that smoking can cause nutrient and oxygen deprivation in cutaneous tissues, decreases collagen and elastin fibres in the dermis, and increases keratinocyte dysplasia.50 These changes reduce skin lipids, sebum and moisture retention, leading to dryness and pruritus of skin.51 52 Therefore, smoking is a potential risk factor for SP. This study also identified drinking alcohol as a potential risk factor for SP. Studies have demonstrated that alcohol consumption could reduce the concentration of carotenoids in the skin.53 Carotenoids can neutralise free radicals, delay premature skin ageing and skin diseases caused by free radicals.53–55 It could be proposed that alcohol consumption may lead to skin diseases by affecting the concentration of carotenoids. The human body cannot synthesise carotenoids in sufficient amounts without relying on a nutrient rich diet including fruit and vegetables. Therefore, monophagism could contribute to reducing the concentration of carotenoids and it could be considered a risk factors for skin diseases. Regrettably, the specific types of monophagism wasn't pointed out in the included study, which prevented further analysis and discussion. We expect that follow-up studies will explore and investigate this. In addition, point out the participants' dietary structure and specific types of monophagism.

    Although this study indicated smoking, excessive drinking and monophagism were associated with an increased risk of SP, all the studies included in the meta-analysis were cross-sectional. Consequently, It is not possible to infer on the causality between exposure and outcomes. Further studies are needed to confirm these findings. In addition to the three risk factors identified through the meta-analyses, the included studies also showed that the risk factors for SP also include age, xerosis, astriction, less water intake, bathing with soap, bathing too frequently, malignant tumour, chronic illness, excessive drinking, insomnia and contact with animals.

    To the best of our knowledge, this study is the first to provide a systematic review of SP prevalence and risk factors. However, several limitations of this study should be noted. First, The epidemiological data on SP was only from Norway, China, Turkey, Britain and Denmark, which cannot be generalised to the worldwide population. Second, the methods of identifying SP varied among the included studies, the definitions of SP may not be uniform among investigators and researchers in different countries, the study of different countries may not be unified in assessing the prevalence of SP, making it difficult to analyse the prevalence of SP using a gold standard method. These limitations make we less confident that the final estimate is close to a ‘true’ estimate. Considering these limitations, further studies will be needed to better understand the prevalence and risk factors of SP worldwide.

    Conclusion

    In conclusion, this study found the prevalence of SP was 21.04%. Individuals who were older, male or living in Turkey and China were associated with a higher prevalence of SP. Additionally, among health examination centres, nursing homes and communities, the highest detection rate of SP was found in the health examination centres. Smoking, excessive drinking and monophagism were possible individual risk factors for SP.

    Data availability statement

    Data are available in a public, open access repository. All data relevant to the study are included in the article or uploaded as online supplemental information.

    Ethics statements

    Patient consent for publication

    Ethics approval

    This study does not involve human participants.

    References

    1. ↵
      1. Valdes-Rodriguez R,
      2. Mollanazar NK,
      3. González-Muro J, et al
      . Itch prevalence and characteristics in a Hispanic geriatric population: a comprehensive study using a standardized itch questionnaire. Acta Derm Venereol 2015;95:417–21.doi:10.2340/00015555-1968pmid:http://www.ncbi.nlm.nih.gov/pubmed/25203328
      OpenUrlPubMed
    2. ↵
      1. Hosseinpoor AR,
      2. Bergen N,
      3. Chatterji S
      . Socio-demographic determinants of caregiving in older adults of low- and middle-income countries. Age Ageing 2013;42:330–8.doi:10.1093/ageing/afs196pmid:http://www.ncbi.nlm.nih.gov/pubmed/23612865
      OpenUrlCrossRefPubMed
    3. ↵
      1. Darjani A,
      2. Mohtasham-Amiri Z,
      3. Mohammad Amini K, et al
      . Skin disorders among elder patients in a referral center in northern Iran (2011). Dermatol Res Pract 2013;2013:193205. doi:10.1155/2013/193205pmid:http://www.ncbi.nlm.nih.gov/pubmed/23935606
      OpenUrlPubMed
    4. ↵
      1. Reszke R,
      2. Pełka D,
      3. Walasek A, et al
      . Skin disorders in elderly subjects. Int J Dermatol 2015;54:e332–8.doi:10.1111/ijd.12832pmid:http://www.ncbi.nlm.nih.gov/pubmed/26148310
      OpenUrlPubMed
    5. ↵
      1. Zhang Q,
      2. Wang HZ,
      3. Gao J
      . Effect of traditional Chinese medicine desire adjustment therapy on sleep quality in patients with senile skin pruritus. Chin J Nurs 2017;52:161–5.
      OpenUrl
    6. ↵
      1. Ständer S,
      2. Weisshaar E,
      3. Mettang T, et al
      . Clinical classification of itch: a position paper of the International forum for the study of itch. Acta Derm Venereol 2007;87:291–4.doi:10.2340/00015555-0305pmid:http://www.ncbi.nlm.nih.gov/pubmed/17598029
      OpenUrlCrossRefPubMedWeb of Science
    7. ↵
      1. Clerc C-J,
      2. Misery L,
      3. Venereologica ML
      . A literature review of senile pruritus: from diagnosis to treatment. Acta Derm Venereol 2017;97:433–40.doi:10.2340/00015555-2574pmid:http://www.ncbi.nlm.nih.gov/pubmed/27840888
      OpenUrlPubMed
    8. ↵
      1. Reich A,
      2. Ständer S,
      3. Szepietowski JC
      . Pruritus in the elderly. Clin Dermatol 2011;29:15–23.doi:10.1016/j.clindermatol.2010.07.002pmid:http://www.ncbi.nlm.nih.gov/pubmed/21146727
      OpenUrlPubMed
    9. ↵
      1. Cohen KR,
      2. Frank J,
      3. Salbu RL, et al
      . Pruritus in the elderly: clinical approaches to the improvement of quality of life. P T 2012;37:227–39.pmid:http://www.ncbi.nlm.nih.gov/pubmed/22593635
      OpenUrlPubMed
    10. ↵
      1. Zhang Q,
      2. Gao J,
      3. Shi LH
      . Effect of traditional Chinese medicine desire adjustment therapy on symptom and the quality of life in patients with senile skin pruritu. Chin J Geront 2016;36:4897–9.
      OpenUrl
    11. ↵
      1. Teoh YL,
      2. Teo RY,
      3. Yeo B
      . Elderly hospitalised Patients-The impact of itch and its prevalence. Ann Acad Med Singapore 2016;45:134–7.
      OpenUrl
    12. ↵
      1. Thaipisuttikul Y
      . Pruritic skin diseases in the elderly. J Dermatol 1998;25:153–7.doi:10.1111/j.1346-8138.1998.tb02371.x
      OpenUrlPubMed
    13. ↵
      1. Caretti KL,
      2. Mehregan DR,
      3. Mehregan DA
      . A survey of self-reported skin disease in the elderly African-American population. Int J Dermatol 2015;54:1034–8.doi:10.1111/ijd.12520pmid:http://www.ncbi.nlm.nih.gov/pubmed/25428122
      OpenUrlPubMed
    14. ↵
      1. Rubegni P,
      2. Poggiali S,
      3. Nami N, et al
      . Skin diseases in geriatric patients: our experience from a public skin outpatient clinic in Siena. G Ital Dermatol Venereol 2012;147:631–6.pmid:http://www.ncbi.nlm.nih.gov/pubmed/23149709
      OpenUrlPubMed
    15. ↵
      1. Liao YH,
      2. Chen KH,
      3. Tseng MP, et al
      . Pattern of skin diseases in a geriatric patient group in Taiwan: a 7-year survey from the outpatient clinic of a university medical center. Dermatology 2001;203:308–13.doi:10.1159/000051778
      OpenUrlCrossRefPubMed
    16. ↵
      1. Reszke R,
      2. Pełka D,
      3. Walasek A, et al
      . Skin disorders in elderly subjects. Int J Dermatol 2015;54:e332–8.doi:10.1111/ijd.12832
      OpenUrlPubMed
    17. ↵
      1. Reszke R,
      2. Białynicki-Birula R,
      3. Lindner K, et al
      . Itch in elderly people: a cross-sectional study. Acta Derm Venereol 2019;99:1016–21.doi:10.2340/00015555-3271
      OpenUrl
    18. ↵
      1. Yang J,
      2. Zhao H,
      3. Zhou Y
      . A case-control study on risk of 410 male senile pruritus. Mod Prevent Med 2009;36:1820–2.
      OpenUrl
    19. ↵
      1. Chen ZH,
      2. HX M,
      3. Xian JF
      . The study on the morbidity of common senile dermatosis in Junjing community in Guangzhou City. J Jinan Univ 2015;36:73–6.
      OpenUrl
    20. ↵
      1. Moher D,
      2. Shamseer L,
      3. Clarke M, et al
      . Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev 2015;4:1. doi:10.1186/2046-4053-4-1
    21. ↵
      1. Zeng XT,
      2. Liu H,
      3. Chen X
      . Meta analysis series 4: quality assessment tools for observational studies. Chin J Evid Based Cardiovasc Med 2012;4:297–9.
      OpenUrl
    22. ↵
      1. Nyaga VN,
      2. Arbyn M,
      3. Aerts M
      . Metaprop: a Stata command to perform meta-analysis of binomial data. Arch Public Health 2014;72:39. doi:10.1186/2049-3258-72-39pmid:http://www.ncbi.nlm.nih.gov/pubmed/25810908
      OpenUrlPubMed
    23. ↵
      1. Barili F,
      2. Parolari A,
      3. Kappetein PA
      . Statistical primer: heterogeneity. random- or fixed-effects model analyses? Interact Cardiovasc Thorac Surg 2018;27:317–21.
      OpenUrl
    24. ↵
      1. Herrmann D,
      2. Sinnett P,
      3. Holmes J, et al
      . Statistical controversies in clinical research: publication bias evaluations are not routinely conducted in clinical oncology systematic reviews. Ann Oncol 2017;28:931–7.doi:10.1093/annonc/mdw691pmid:http://www.ncbi.nlm.nih.gov/pubmed/28039176
      OpenUrlPubMed
    25. ↵
      1. XS L,
      2. BX H,
      3. Yang XQ
      . Investigation of dermatosis in cadres above division level in Changchun. Shenyang Budui Yiyao 2000;13:39.
      OpenUrl
    26. ↵
      1. NL G,
      2. Xie ZH,
      3. Zhang CL
      . A case-control study on risk of 122 simple senile pruritus. Chin J Epidemiol 2006;27:627–9.
      OpenUrl
    27. ↵
      1. Xue SQ
      . Survey on elderly skin disorders of workers in Taigang factory. Chin J Dermatovenereol 2008;22:409–10.
      OpenUrl
    28. ↵
      1. HL N,
      2. XY K,
      3. Qian MQ
      . Analysis of prevalence of elderly itch skin disease in two pension institutions in Shanghai. Chin J Dermato Venerol Integ Trad W Med 2012;11:157–8.
      OpenUrl
    29. ↵
      1. Zhang L
      . The dermatopathic study of Middle—age and elderly Cadres in TaiYuan. Taiyuan, Shanxi, China: Shanxi Medical University, 2012.
    30. ↵
      1. Li L,
      2. Wang T,
      3. Liu XZ
      . Analysis of risk factors and health guidance for senile pruritus. J Mili Surg in Southwest Chin 2014:591–2.
    31. ↵
      1. Wu N,
      2. Zhang DL
      . Investigation and etiological analysis of senile pruritus. Chin J Convalescent Med 2014;23:368–9.
      OpenUrl
    32. ↵
      1. Yang J,
      2. Dou N,
      3. SH M
      . Influencing factors of senile pruritus in Tangshan City. Chin J Geront 2014;34:5205–7.
      OpenUrl
    33. ↵
      1. Hou XF,
      2. Zhang LJ
      . Investigation and analysis of 196 influencing factors of elderly dermatosis. Shaanxi Med 2016;45:1559–60.
      OpenUrl
    34. ↵
      1. Dalgard F,
      2. Svensson A,
      3. Holm J Ø, et al
      . Self-Reported skin morbidity in Oslo. associations with sociodemographic factors among adults in a cross-sectional study. Br J Dermatol 2004;151:452–7.doi:10.1111/j.1365-2133.2004.06058.xpmid:http://www.ncbi.nlm.nih.gov/pubmed/15327554
      OpenUrlCrossRefPubMed
    35. ↵
      1. Tseng H-W,
      2. Lam H-C,
      3. Ger L-P, et al
      . A survey of dermatological diseases among older male adults of a Veterans home in southern Taiwan. Aging Clin Exp Res 2015;27:227–33.doi:10.1007/s40520-014-0260-9pmid:http://www.ncbi.nlm.nih.gov/pubmed/25037106
      OpenUrlPubMed
    36. ↵
      1. Miller IM,
      2. Zarchi K,
      3. Ellervik C, et al
      . Self-Reported skin morbidity in Denmark: a population-based cross-sectional study. Eur J Dermatol 2016;26:281–6.doi:10.1684/ejd.2016.2766pmid:http://www.ncbi.nlm.nih.gov/pubmed/27210463
      OpenUrlPubMed
    37. ↵
      1. Kara PA,
      2. Alatas ET,
      3. Doğan G
      . Prevalence of skin diseases among elderly residing in nursing homes in Mugla. Turk J Geriatr 2017;20:23–9.
      OpenUrl
    38. ↵
      1. Cowdell F,
      2. Dyson J,
      3. Long J, et al
      . Self-Reported skin concerns: an epidemiological study of community-dwelling older people. Int J Older People Nurs 2018;13:12195. doi:10.1111/opn.12195pmid:http://www.ncbi.nlm.nih.gov/pubmed/29577628
      OpenUrlPubMed
    39. ↵
      1. Dyhre-Petersen N,
      2. Gazerani P
      . Presence and characteristics of senile pruritus among Danish elderly living in nursing homes. Future Sci OA 2019;5:Fso399.doi:10.2144/fsoa-2019-0036pmid:http://www.ncbi.nlm.nih.gov/pubmed/31285844
      OpenUrlPubMed
    40. ↵
      1. Xiong F,
      2. Lai YQ,
      3. JX T
      . Epidemiological characteristics of sleep disorders in the Chinese elderly: a meta-analysis. Chin J Evid-Based Med 2020;19:398–403.
      OpenUrl
    41. ↵
      1. Valdes-Rodriguez R,
      2. Stull C,
      3. Yosipovitch G
      . Chronic pruritus in the elderly: pathophysiology, diagnosis and management. Drugs Aging 2015;32:201–15.doi:10.1007/s40266-015-0246-0pmid:http://www.ncbi.nlm.nih.gov/pubmed/25693757
      OpenUrlPubMed
    42. ↵
      1. Patel T,
      2. Yosipovitch G
      . The management of chronic pruritus in the elderly. Skin Therapy Lett 2010;15:5–9.pmid:http://www.ncbi.nlm.nih.gov/pubmed/20844849
      OpenUrlPubMed
    43. ↵
      1. Paul C,
      2. Maumus-Robert S,
      3. Mazereeuw-Hautier J, et al
      . Prevalence and risk factors for xerosis in the elderly: a cross-sectional epidemiological study in primary care. Dermatology 2011;223:260–5.doi:10.1159/000334631pmid:http://www.ncbi.nlm.nih.gov/pubmed/22104182
      OpenUrlPubMed
    44. ↵
      1. Berger TG,
      2. Shive M,
      3. Harper GM
      . Pruritus in the older patient: a clinical review. JAMA 2013;310:2443–50.doi:10.1001/jama.2013.282023pmid:http://www.ncbi.nlm.nih.gov/pubmed/24327039
      OpenUrlPubMed
    45. ↵
      1. Ko M-J,
      2. Yang J-Y,
      3. Wu H-Y, et al
      . Narrowband ultraviolet B phototherapy for patients with refractory uraemic pruritus: a randomized controlled trial. Br J Dermatol 2011;165:633–9.doi:10.1111/j.1365-2133.2011.10448.xpmid:http://www.ncbi.nlm.nih.gov/pubmed/21668425
      OpenUrlCrossRefPubMed
    46. ↵
      1. Reich A,
      2. Ständer S,
      3. Szepietowski JC
      . Drug-Induced pruritus: a review. Acta Derm Venereol 2009;89:236–44.doi:10.2340/00015555-0650pmid:http://www.ncbi.nlm.nih.gov/pubmed/19479118
      OpenUrlCrossRefPubMedWeb of Science
    47. ↵
      1. Zhang ZJ,
      2. Zhu J,
      3. Me H
      . Advances in the pathogenesis of senile pruritus. Chin J Geront 2018;38:4598–600.
      OpenUrl
    48. ↵
      1. Liu YS
      . Endocrine system characteristics and diseases of the elderly. Chin J Geriatr 2005;24:637–9.
      OpenUrl
    49. ↵
      1. Tey HL,
      2. Yosipovitch G
      . Itch in ethnic populations. Acta Derm Venereol 2010;90:227–34.doi:10.2340/00015555-0867pmid:http://www.ncbi.nlm.nih.gov/pubmed/20526537
      OpenUrlCrossRefPubMed
    50. ↵
      1. Leow YH,
      2. Maibach HI
      . Cigarette smoking, cutaneous vasculature, and tissue oxygen. Clin Dermatol 1998;16:579–84.doi:10.1016/s0738-081x(98)00042-xpmid:http://www.ncbi.nlm.nih.gov/pubmed/9787969
      OpenUrlPubMedWeb of Science
    51. ↵
      1. Farage MA,
      2. Miller KW,
      3. Elsner P, et al
      . Intrinsic and extrinsic factors in skin ageing: a review. Int J Cosmet Sci 2008;30:87–95.doi:10.1111/j.1468-2494.2007.00415.xpmid:http://www.ncbi.nlm.nih.gov/pubmed/18377617
      OpenUrlCrossRefPubMed
    52. ↵
      1. Friedman O
      . Changes associated with the aging face. Facial Plast Surg Clin North Am 2005;13:371–80.doi:10.1016/j.fsc.2005.04.004pmid:http://www.ncbi.nlm.nih.gov/pubmed/16085282
      OpenUrlCrossRefPubMed
    53. ↵
      1. Lademann J,
      2. Meinke MC,
      3. Sterry W, et al
      . Carotenoids in human skin. Exp Dermatol 2011;20:377–82.doi:10.1111/j.1600-0625.2010.01189.xpmid:http://www.ncbi.nlm.nih.gov/pubmed/21366698
      OpenUrlCrossRefPubMed
    54. ↵
      1. Berson DS
      . Natural antioxidants. J Drugs Dermatol 2008;7:s7–12.pmid:http://www.ncbi.nlm.nih.gov/pubmed/18681153
      OpenUrlPubMed
    55. ↵
      1. Stahl W,
      2. Sies H
      . Bioactivity and protective effects of natural carotenoids. Biochim Biophys Acta 2005;1740:101–7.doi:10.1016/j.bbadis.2004.12.006pmid:http://www.ncbi.nlm.nih.gov/pubmed/15949675
      OpenUrlPubMed

    Supplementary materials

    • Supplementary Data

      This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.

    Footnotes

    • Contributors SC and FZ contributed equally to this study. SC conceived and participated in the design of this review. SC and FZ performed the literature searches, study selection, data extraction and assessed the risk of bias. SC and FZ drafted the manuscript. YX helped in performing the analysis with constructive discussions. SC revised the final version. All authors read and approved the final manuscript. SC is responsible for the overall content as the guarantor.

    • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

    • Competing interests None declared.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.