{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T04:26:18Z","timestamp":1791260778422,"version":"4.1.0"},"reference-count":38,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2019,10,24]],"date-time":"2019-10-24T00:00:00Z","timestamp":1571875200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2019,10,24]],"date-time":"2019-10-24T00:00:00Z","timestamp":1571875200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Public Health"],"published-print":{"date-parts":[[2019,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n              <jats:sec>\n                <jats:title>Background<\/jats:title>\n                <jats:p>Many studies have reported the impact of air pollution on cardiovascular disease (CVD), but few of these studies were conducted in severe haze-fog areas. The present study focuses on the impact of different air pollutant concentrations on daily CVD outpatient visits in a severe haze-fog city.<\/jats:p>\n              <\/jats:sec>\n              <jats:sec>\n                <jats:title>Methods<\/jats:title>\n                <jats:p>Data regarding daily air pollutants and outpatient visits for CVD in 2013 were collected, and the association between six pollutants and CVD outpatient visits was explored using the least squares mean (LSmeans) and logistic regression. Adjustments were made for days of the week, months, air temperature and relative humidity.<\/jats:p>\n              <\/jats:sec>\n              <jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>The daily CVD outpatient visits for particulate matter (PM<jats:sub>10<\/jats:sub> and PM<jats:sub>2.5<\/jats:sub>), sulphur dioxide (SO<jats:sub>2<\/jats:sub>), nitrogen dioxide (NO<jats:sub>2<\/jats:sub>), carbon monoxide (CO), and ozone (O<jats:sub>3<\/jats:sub>) in the 90th-quantile group were increased by 30.01, 29.42, 17.68, 14.98, 29.34%, and\u2009\u2212\u200919.87%, respectively, compared to those in the &lt;10th-quantile group. Odds ratios (ORs) and 95% confidence intervals (CIs) for the increase in daily CVD outpatient visits in PM<jats:sub>10<\/jats:sub> 300- and 500-\u03bcg\/m<jats:sup>3<\/jats:sup>, PM<jats:sub>2.5<\/jats:sub> 100- and 300-\u03bcg\/m<jats:sup>3<\/jats:sup> and CO 3-mg\/m<jats:sup>3<\/jats:sup> groups were 2.538 (1.070\u20136.020), 7.781 (1.681\u201336.024), 3.298 (1.559\u20136.976), 8.72 (1.523\u201349.934), and 5.808 (1.016\u201333.217), respectively, and their corresponding attributable risk percentages (AR%) were 60.6, 87.15, 69.68, 88.53 and 82.78%, respectively. The strongest associations for PM<jats:sub>10<\/jats:sub>, PM<jats:sub>2.5<\/jats:sub> and CO were found only in lag 0 and lag 1. The ORs for the increase in CVD outpatient visits per increase in different units of the six pollutants were also analysed.<\/jats:p>\n              <\/jats:sec>\n              <jats:sec>\n                <jats:title>Conclusions<\/jats:title>\n                <jats:p>All five air pollutants except O<jats:sub>3<\/jats:sub> were positively associated with the increase in daily CVD outpatient visits in lag 0. The high concentrations of PM<jats:sub>10<\/jats:sub>, PM<jats:sub>2.5<\/jats:sub> and CO heightened not only the percentage but also the risk of increased daily CVD outpatient visits. PM<jats:sub>10<\/jats:sub>, PM<jats:sub>2.5<\/jats:sub> and CO may be the main factors of CVD outpatient visits.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1186\/s12889-019-7690-4","type":"journal-article","created":{"date-parts":[[2019,10,25]],"date-time":"2019-10-25T17:11:11Z","timestamp":1572023471000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Air pollutants and outpatient visits for cardiovascular disease in a severe haze-fog city: Shijiazhuang, China"],"prefix":"10.1186","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9577-5033","authenticated-orcid":false,"given":"Fengzhu","family":"Tan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weijie","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sufen","family":"Qi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haidong","family":"Kan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinpei","family":"Yu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duanyang","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bin","family":"Xu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fan","family":"Meng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sicen","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2019,10,24]]},"reference":[{"key":"7690_CR1","doi-asserted-by":"publisher","first-page":"1173","DOI":"10.1093\/aje\/kwr425","volume":"175","author":"R Chen","year":"2012","unstructured":"Chen R, Kan H, Chen B, Huang W, Bai Z, Song G, et al. Association of particulate air pollution with daily mortality: The china air pollution and health effects study. Am J Epidemiol. 2012;175:1173\u201381.","journal-title":"Am J Epidemiol"},{"key":"7690_CR2","doi-asserted-by":"publisher","first-page":"8","DOI":"10.1016\/S0013-9351(02)00022-1","volume":"91","author":"MS Goldberg","year":"2003","unstructured":"Goldberg MS, Burnett RT, Valois MF, Flegel K, Bailar JC III, Brook J, et al. Associations between ambient air pollution and daily mortality among persons with congestive heart failure. Environ Res. 2003;91:8\u201320.","journal-title":"Environ Res"},{"key":"7690_CR3","doi-asserted-by":"publisher","first-page":"625","DOI":"10.1093\/aje\/kwk051","volume":"165","author":"JL Peel","year":"2007","unstructured":"Peel JL, Metzger KB, Klein M, et al. Ambient air pollution and cardiovascular emergency department visits in potentially sensitive groups. Am J Epidemiol. 2007;165:625\u201333.","journal-title":"Am J Epidemiol"},{"key":"7690_CR4","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1097\/01.EDE.0000101748.28283.97","volume":"15","author":"KB Metzger","year":"2004","unstructured":"Metzger KB, Tolbert PE, Klein M, Flanders WD, Mulholland JA, Tolbert PE, et al. Ambient air pollution and cardiovascular emergency department visits. Epidemiology. 2004;15:46\u201356.","journal-title":"Epidemiology."},{"key":"7690_CR5","doi-asserted-by":"publisher","first-page":"23","DOI":"10.1093\/oxfordjournals.aje.a117541","volume":"142","author":"J Schwartz","year":"1995","unstructured":"Schwartz J, Morris R. Air pollution and hospital admissions for cardiovascular disease in Detroit, Michigan. Am J Epidemiol. 1995;142:23\u201335.","journal-title":"Am J Epidemiol"},{"key":"7690_CR6","doi-asserted-by":"publisher","first-page":"321","DOI":"10.2188\/jea.JE20140030","volume":"24","author":"A Zhao","year":"2014","unstructured":"Zhao A, Chen R, Kuang X, Kan H. Ambient Air Pollution and Daily Outpatient Visits for Cardiac Arrhythmia in Shanghai, China. J Epidemiology. 2014;24:321\u20136.","journal-title":"J Epidemiology"},{"key":"7690_CR7","doi-asserted-by":"publisher","first-page":"4826","DOI":"10.1016\/j.scitotenv.2009.05.022","volume":"407","author":"Y Guo","year":"2009","unstructured":"Guo Y, Jia Y, Pan X, Liu L, Wichmann HE. The association between fine particulate air pollution and hospital emergency room visits for cardiovascular diseases in Beijing, China. Sci Total Environ. 2009;407:4826\u201330.","journal-title":"Sci Total Environ"},{"key":"7690_CR8","doi-asserted-by":"publisher","first-page":"580","DOI":"10.1136\/jech.53.9.580","volume":"53","author":"CM Wong","year":"1999","unstructured":"Wong CM, Ma S, Hedley AJ, Lam TH. Does ozone have any effect on daily hospital admissions for circulatory diseases? J Epidemiol Community Health. 1999;53:580\u20131.","journal-title":"J Epidemiol Community Health"},{"key":"7690_CR9","doi-asserted-by":"publisher","first-page":"1361","DOI":"10.2105\/AJPH.85.10.1361","volume":"85","author":"RD Morris","year":"1995","unstructured":"Morris RD, Naumova EN, Munasinghe RL. Ambient air pollution and hospitalization for congestive heart failure among elderly people in seven large US cities. Am J Public Health. 1995;85:1361\u20135.","journal-title":"Am J Public Health"},{"key":"7690_CR10","doi-asserted-by":"publisher","first-page":"1039","DOI":"10.1016\/S0140-6736(13)60898-3","volume":"382","author":"AS Shah","year":"2013","unstructured":"Shah AS, Langrish JP, Nair H, Mcallister DA, Hunter AL, Donaldson K, et al. Global association of air pollution and heart failure: a systematic review and meta-analysis. Lancet. 2013;382:1039\u201348.","journal-title":"Lancet."},{"key":"7690_CR11","doi-asserted-by":"publisher","first-page":"713","DOI":"10.1001\/jama.2012.126","volume":"307","author":"H Mustafi\u0107","year":"2012","unstructured":"Mustafi\u0107 H, Jabre P, Caussin C, Murad MH, Escolano S, Tafflet M, et al. Main air pollutants and myocardial infarction: a systematic review and meta-analysis. JAMA. 2012;307:713\u201321.","journal-title":"JAMA."},{"key":"7690_CR12","doi-asserted-by":"publisher","first-page":"747","DOI":"10.1289\/ehp.1307337","volume":"122","author":"JP Langrish","year":"2014","unstructured":"Langrish JP, Watts SJ, Hunter AJ, Shah ASV, Bosson JA, Unosson J, et al. Controlled Exposures to Air Pollutants and Risk of Cardiac Arrhythmia. Environ Health Perspect. 2014;122:747\u201353.","journal-title":"Environ Health Perspect"},{"key":"7690_CR13","doi-asserted-by":"publisher","first-page":"427","DOI":"10.1289\/ehp.00108427","volume":"108","author":"WS Linn","year":"2000","unstructured":"Linn WS, Szlachcic Y, Gong H, Kinney PL, Berhane KT. Air pollution and daily hospital admissions in metropolitan Los Angeles. Environ Health Perspect. 2000;108:427\u201334.","journal-title":"Environ Health Perspect"},{"issue":"3","key":"7690_CR14","doi-asserted-by":"publisher","first-page":"e0151119","DOI":"10.1371\/journal.pone.0151119","volume":"11","author":"X Ye","year":"2016","unstructured":"Ye X, Peng L, Kan H, Wang W, Geng F, Mu Z, et al. Acute Effects of Particulate Air Pollution on the Incidence of Coronary Heart Disease in Shanghai, China. Plos One. 2016;11(3):e0151119. \n                    https:\/\/doi.org\/10.1371\/journal.pone.0151119\n                    \n                  .","journal-title":"Plos One"},{"key":"7690_CR15","first-page":"394","volume":"47","author":"M Wang","year":"2013","unstructured":"Wang M. Situation and Countermeasures of Influenza in China in 2013. Chin J Prev Med. 2013;47:394\u20137.","journal-title":"Chin J Prev Med"},{"key":"7690_CR16","doi-asserted-by":"publisher","first-page":"1534","DOI":"10.1161\/01.CIR.0000013838.94747.64","volume":"105","author":"RD Brook","year":"2002","unstructured":"Brook RD, Brook JR, Urch B, Vincent R, Rajagopalan S, Silverman F. Inhalation of fine particulate air pollution and ozone causes acute arterial vasoconstriction in healthy adults. Circulation. 2002;105:1534\u20136.","journal-title":"Circulation."},{"key":"7690_CR17","doi-asserted-by":"publisher","first-page":"42","DOI":"10.1186\/1476-069X-8-42","volume":"8","author":"VB Haley","year":"2009","unstructured":"Haley VB, Talbot TO, Felton HD. Surveillance of the short-term impact of fine particle air pollution on cardiovascular disease hospitalizations in New York State. Environ Health. 2009;8:42. \n                    https:\/\/doi.org\/10.1186\/1476-069X-8-42\n                    \n                  .","journal-title":"Environ Health"},{"key":"7690_CR18","doi-asserted-by":"publisher","first-page":"1018","DOI":"10.1289\/ehp.8674","volume":"114","author":"AG Barnett","year":"2006","unstructured":"Barnett AG, Williams GM, Schwartz J, et al. The effects of air pollution on hospitalizations for cardiovascular disease in elderly people in Australian and New Zealand cities. Environ Health Perspect. 2006;114:1018\u201323.","journal-title":"Environ Health Perspect"},{"key":"7690_CR19","doi-asserted-by":"publisher","first-page":"1030","DOI":"10.1093\/aje\/kwi135","volume":"161","author":"GA Wellenius","year":"2005","unstructured":"Wellenius GA, Bateson TF, Mittleman MA, Schwartz J. Particulate air pollution and the rate of hospitalization for congestive heart failure among medicare beneficiaries in Pittsburgh,Pennsylvania. Am J Epidemiol. 2005;161:1030\u20136.","journal-title":"Am J Epidemiol"},{"key":"7690_CR20","doi-asserted-by":"publisher","first-page":"S29","DOI":"10.1038\/sj.jes.7500625","volume":"17","author":"PE Tolberta","year":"2007","unstructured":"Tolberta PE, Kleina M, Peelb JL, et al. Multipollutant modeling issues in a study of ambient air quality and emergency department visits in Atlanta. J Expo Sci Environ Epidemiol. 2007;17:S29\u20135.","journal-title":"J Expo Sci Environ Epidemiol"},{"key":"7690_CR21","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/1476-069X-8-25","volume":"8","author":"DM Stieb","year":"2009","unstructured":"Stieb DM, Szyszkowicz M, Rowe BH, Leech JA. Air pollution and emergency department visits for cardiac and respiratory conditions: a multi-city time-series analysis. Environ Health. 2009;8:1\u201313. \n                    https:\/\/doi.org\/10.1186\/1476-069X-8-25\n                    \n                  .","journal-title":"Environ Health"},{"key":"7690_CR22","doi-asserted-by":"publisher","first-page":"355","DOI":"10.1289\/ehp.01109355","volume":"109","author":"F Ye","year":"2001","unstructured":"Ye F, Piver WT, Ando M, Portier CJ. Effects of temperature and air pollutants on cardiovascular and respiratory diseases for males and females older than 65 years of age in Tokyo, July and August 1980\u20131995. Environ Health Perspect. 2001;109:355\u20139.","journal-title":"Environ Health Perspect"},{"key":"7690_CR23","doi-asserted-by":"publisher","first-page":"414","DOI":"10.1097\/EDE.0b013e3181d5c021","volume":"21","author":"V Belleudi","year":"2010","unstructured":"Belleudi V, Faustini A, Stafoggia M, Cattani G, Marconi A, Perucci CA, et al. Impact of fine and ultrafine particles on emergency hospital admissions for cardiac and respiratory diseases. Epidemiology. 2010;21:414\u201323.","journal-title":"Epidemiology."},{"key":"7690_CR24","doi-asserted-by":"publisher","first-page":"899","DOI":"10.1080\/08958370701479406","volume":"19","author":"IM Lee","year":"2007","unstructured":"Lee IM, Tsai SS, Ho CK, Chiu HF, Yang CY. Air pollution and hospital admissions for congestive heart failure in a tropical city: Kaohsiung, Taiwan. Inhal Toxicol. 2007;19:899\u2013904.","journal-title":"Inhal Toxicol"},{"key":"7690_CR25","doi-asserted-by":"publisher","first-page":"130","DOI":"10.1080\/00039899909602248","volume":"54","author":"RT Burnett","year":"1999","unstructured":"Burnett RT, Smith-Doiron M, Stieb D, Cakmak S, Brook JR. Effects of particulate and gaseous air pollution on cardiorespiratory hospitalizations. Arch Environ Health. 1999;54:130\u20139.","journal-title":"Arch Environ Health"},{"key":"7690_CR26","doi-asserted-by":"publisher","first-page":"679","DOI":"10.1136\/oem.56.10.679","volume":"56","author":"TW Wong","year":"1999","unstructured":"Wong TW, Lau TS, Yu TS, Neller A, Wong SL, Tam W. Air pollution and hospital admissions for respiratory and cardiovascular diseases in Hong Kong. Occup Environ Med. 1999;56:679\u201383.","journal-title":"Occup Environ Med"},{"key":"7690_CR27","doi-asserted-by":"publisher","first-page":"413","DOI":"10.1097\/00001648-200107000-00011","volume":"12","author":"HJ Kwon","year":"2001","unstructured":"Kwon HJ, Cho SH, Nyberg F, Pershagen G. Effects of ambient air pollution on daily mortality in a cohort of patients with congestive heart failure. Epidemiology. 2001;12:413\u20139.","journal-title":"Epidemiology."},{"key":"7690_CR28","doi-asserted-by":"publisher","first-page":"1426","DOI":"10.1056\/NEJM198911233212102","volume":"321","author":"EN Allred","year":"1989","unstructured":"Allred EN, Bleecker ER, Chaitman BR, Dahms TE, Gottlieb SO, Hackney JD. Short-term effects of carbon monoxide exposure on the exercise performance of subjects with coronary artery disease. N Engl J Med. 1989;321:1426\u201332.","journal-title":"N Engl J Med"},{"key":"7690_CR29","doi-asserted-by":"publisher","first-page":"949","DOI":"10.1161\/CIRCULATIONAHA.109.851113","volume":"120","author":"ML Bell","year":"2009","unstructured":"Bell ML, Peng RD, Dominici F, Samet JM. Emergency hospital admissions for cardiovascular diseases and ambient levels of carbon monoxide: results for 126 United States urban counties, 1999\u20132005. Circulation. 2009;120:949\u201355.","journal-title":"Circulation."},{"key":"7690_CR30","doi-asserted-by":"publisher","first-page":"649","DOI":"10.1289\/ehp.98106649","volume":"106","author":"RD Morris","year":"1998","unstructured":"Morris RD, Naumova EN. Carbon monoxide and hospital admissions for congestive heart failure: evidence of an increased effect at low temperatures. Environ Health Perspect. 1998;106:649\u201353.","journal-title":"Environ Health Perspect"},{"key":"7690_CR31","doi-asserted-by":"publisher","first-page":"328","DOI":"10.1136\/jech.2005.037978","volume":"60","author":"F Ballester","year":"2006","unstructured":"Ballester F, Rodr\u00edguez P, I\u00f1\u00edguez C, Saez M, Daponte A, Gal\u00e1n I, et al. Air pollution and cardiovascular admissions association in Spain: results within the EMECAS project. J Epidemiol Community Health. 2006;60:328\u201336.","journal-title":"J Epidemiol Community Health"},{"key":"7690_CR32","doi-asserted-by":"publisher","first-page":"17","DOI":"10.1097\/00001648-199901000-00005","volume":"10","author":"J Schwartz","year":"1999","unstructured":"Schwartz J. Air pollution and hospital admissions for heart disease in eight US counties. Epidemiology. 1999;10:17\u201322.","journal-title":"Epidemiology."},{"key":"7690_CR33","doi-asserted-by":"publisher","first-page":"162","DOI":"10.1097\/00001648-199703000-00007","volume":"8","author":"RT Burnett","year":"1997","unstructured":"Burnett RT, Dales RE, Brook JR, Raizenne ME, Krewski D. Association between ambient carbon monoxide levels and hospitalizations for congestive heart failure in the elderly in 10 Canadian cities. Epidemiology. 1997;8:162\u20137.","journal-title":"Epidemiology."},{"key":"7690_CR34","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1016\/S0002-9343(89)80476-0","volume":"87","author":"RM Bersin","year":"1989","unstructured":"Bersin RM, Chatterjee K, Al A. Metabolic and hemodynamic consequences of sodium bicarbonate administration in patients with heart disease. Am J Med. 1989;87:7\u201314.","journal-title":"Am J Med"},{"key":"7690_CR35","doi-asserted-by":"publisher","first-page":"491","DOI":"10.1378\/chest.97.2.491","volume":"97","author":"AL Marius-Nunez","year":"1990","unstructured":"Marius-Nunez AL. Myocardial infarction with normal coronary arteries after acute exposure to carbon monoxide. Chest. 1990;97:491\u20134.","journal-title":"Chest."},{"key":"7690_CR36","doi-asserted-by":"publisher","first-page":"361","DOI":"10.1080\/00039896.1989.9935908","volume":"44","author":"MT Kleinman","year":"1989","unstructured":"Kleinman MT, Davidson DM, Vandagriff RB, Caiozzo V, Whittenberger JL. Effects of short-term exposure to carbon monoxide in subjects with coronary artery disease. Arch Environ Health. 1989;44:361\u20139.","journal-title":"Arch Environ Health"},{"key":"7690_CR37","doi-asserted-by":"publisher","first-page":"393","DOI":"10.1289\/ehp.1103715","volume":"120","author":"Y Tao","year":"2012","unstructured":"Tao Y, Huang W, Huang X, Zhong L, Lu S, Li Y. Estimated acute effects of ambient ozone and nitrogen dioxide on mortality in the Pearl River delta of southern China. Environ Health Perspect. 2012;120:393\u20138.","journal-title":"Environ Health Perspect"},{"key":"7690_CR38","first-page":"99","volume":"33","author":"Y Chen","year":"2017","unstructured":"Chen Y, Zhang J, Huang Z. Spatial-temporal variation of surface ozone in Guangzhou and Its relations with meteorological factors. Environ Monit China. 2017;33:99\u2013109.","journal-title":"Environ Monit China"}],"container-title":["BMC Public Health"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1186\/s12889-019-7690-4.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/link.springer.com\/article\/10.1186\/s12889-019-7690-4\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1186\/s12889-019-7690-4.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,10,22]],"date-time":"2020-10-22T23:09:13Z","timestamp":1603408153000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmcpublichealth.biomedcentral.com\/articles\/10.1186\/s12889-019-7690-4"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,10,24]]},"references-count":38,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2019,12]]}},"alternative-id":["7690"],"URL":"https:\/\/doi.org\/10.1186\/s12889-019-7690-4","relation":{},"ISSN":["1471-2458"],"issn-type":[{"value":"1471-2458","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,10,24]]},"assertion":[{"value":"16 August 2019","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"25 September 2019","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"24 October 2019","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"We only collected the total number of CVD outpatient visits, and the selection was not related to outpatients\u2019 personal privacy (i.e., not including personal name, gender, ethnicity, body weight, etc.), and the data belong to de-identification. The study protocol was approval by Medical Ethics Committee in Hebei Medical University (No.20180062).","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors declare that they have no competing interests.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"1366"}}