key: cord-0840778-ljicdm13 authors: Mosaferchi, Saeedeh; Sharif-Paghaleh, Ehsan; Mortezapour, Alireza; Heidarimoghadam, Rashid title: The first Ramadan during COVID-19 pandemic: 1.8 billion Muslims should fast or not? date: 2020-04-30 journal: Metabolism DOI: 10.1016/j.metabol.2020.154253 sha: f0f8a3a2314c6799755e5ea5242b79928b75cb7c doc_id: 840778 cord_uid: ljicdm13 nan J o u r n a l P r e -p r o o f With great interest we have read the recent article entitled" Fasting glucagon concentrations are associated with longitudinal decline of β-cell function in non-diabetic humans" which was published in your valuable journal [1] . We want to congratulate the authors for this successful article, and make a new contribution about fasting during COVID-19 pandemic. In early December, 2019, a novel coronavirus emerged in China [2] . Due to high rate of transmission of the disease, officially confirmed cases have been reported in most countries around the world [3, 4] . With the introduction of the disease as a pandemic, the importance of COVID-19 is increasing day by day [5] . Also, the confirmed cases of this disease in Muslimmajority countries are prevalent [6] [7] [8] . 1.8 billion Muslims live in more than 180 countries around the world [7, 9] . One of the main activities of Muslims in less than one month later (Ramadan: the ninth month in the Islamic calendar) is fasting [10] . To date, various studies have been conducted on the health effects of fasting [11, 12] . Majority of them, studied the impact of fasting on the lipid profile, diabetes and, body weight [13] . Also recent studies have shown the effect of fasting on the immune system [14, 15] . It can be concluded that the results of previous studies on the immune system have been inconsistent. With the increasing importance of COVID-19, a fundamental question needs further investigation. During the outbreak of new corona, healthy Muslims must fast in this Ramadan as in previous years? In the next section we briefly reported some concerns. Due to suppression of immune system, patients with or recently recovered from cancer, are susceptible to COVID-19 [16, 17] . In the one hand, the effect of fasting on suppressing immune system remains unclear [14, 15] and on the other hand recent review study reveals the positive effect of fasting during Ramadan on treatment of cancer [18] . Further confirmed protocols and guidelines must produce to clarify the status of fasting or not fasting for Muslims. Beginning of the Ramadan is considered for reducing smoking among Muslims. However, only little studies have shown the effect of smoking on increasing the chance of COVID-19 [19] , more studies are needed in this regard. Fasting glucagon concentrations are associated with longitudinal decline of β-cell function in non-diabetic humans The effect of control strategies to reduce social mixing on outcomes of the COVID-19 epidemic in Wuhan, China: a modelling study National UK programme of community health workers for COVID-19 response COVID-19 in Europe: the Italian lesson. The Lancet Coronavirus disease COVID-19 battle during the toughest sanctions against Iran. The Lancet COVID-19: preparing for superspreader potential among Umrah pilgrims to Saudi Arabia The first COVID-19 case in Afghanistan acquired from Iran. The Lancet Infectious Diseases World's Muslim population more widespread than you might think Recommendations for Management of Diabetes During Ramadan Brugada syndrome diagnosed after Ramadan. The Lancet Ramadan: health effects of fasting Ramadan fasting and diabetes Fasting-Refeeding Impacts Immune Cell Dynamics and Mucosal Immune Responses When Fasting Gets Tough, the Tough Immune Cells Get Going-or Die Cancer care in the time of COVID-19. The Lancet Oncology Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China Molecular Mechanisms and Clinical Applications Is nicotine exposure linked to cardiopulmonary vulnerability to COVID-19 in the general population? Are patients with hypertension and diabetes mellitus at increased risk for COVID-19 infection?