In 1951, Milano Metropolitan Area counted two Million inhabitants. The present population of the Milano Area is 3.227.264 (23% over 65 y) [15]. Starting from 1971 single household increased dramatically from 19.4 to 44.8% of the total [15]. In 2019, 315.000 inhabitants were 65 years old or more [15]. Obesity prevalence in Lombardia region is 7.9% whilst overweight people are 27.5% of the total population. Full sedentariness involve 24% of the resident population with only 35% of inhabitants exercising regularly [19].
Our study confirms the ominous link between urbanization process and diabetes mellitus and obesity in Milano Metropolitan Area [15]. Unfortunately, other chronic-degenerative diseases like hypertension, Chronic Obstructive Pulmonary Disease (COPD) are also more frequent in urban environment rather than in countryside [19]. In the present report, we provide a photograph of the prevalence of diabetes mellitus and obesity in Milano Metropolitan Area in the year 2019. We utilized official data from ISTAT or ATS of Milano Metropolitan Area, data that are publicly available and consultable by general population [14, 15].
Up-to-date, no study has specifically assessed the difference in prevalence of diabetes between the Milano Metropolitan Area and Italian rural areas. Nonetheless, the South of Italy, less urbanized and industrialized than the North of Italy, has an higher prevalence of diabetes mellitus [20]. Interestingly, a similar pattern of high prevalence of diabetes mellitus in rural areas was reported in China [18].
The first photo shoot indicates over 1% difference in diabetes prevalence between Milano downtown (the City) and peripheral ASSTs (the Periphery), with the highest prevalence in the ASST North Milano (Fig. 1). Several factors may explain this difference: a. percent of inhabitants over 65 in different ASST correlates directly with diabetes prevalence in that area (Figs. 2, 3, 4); b. social and economic factors like unemployment rate correlate directly with prevalence of diabetes mellitus (Fig. 5); c. in contrast, level of instruction correlates inversely with percent of affected inhabitants (Fig. 6).
The difference in prevalence between downtown Milano and its peripheries is relevant and deserves several considerations about potential explanations. (1) Genetic/ethnic differences in the resident population should be considered first. Milano has a foreign resident population constituted by 30.9% Asian, European (29,2%), African (21,9%) or South American (18,2%) ancestry. This determines a wider genetic array and therefore different predisposition to diabetes [21]. (2) The Milano Metropolitan Area is located in the middle of the Po Valley, a lowland with a degree of air pollution among the highest ones in Continental Europe. Pollution level differs between downtown Milano and its peripheries. Since air pollution was associated to a higher rate of diabetes and considering that the Northern Areas of Milano are much more industrialized than downtown and Southern Milano areas, this could partially explain the difference in prevalence between ASSTs [22]. (3) An additional environmental factor to explain the difference in diabetes prevalence is external temperature [23]. Global warming has been linked to the world-wide diabesity pandemic [24]. Due to different models of urbanization, external temperature may differ up to one Celsius degree in different Metropolitan isles [25]. Populations living in areas exposed to a higher mean temperature may be exposed to higher rates of obesity and diabetes. The principal underlying pathogenic mechanism is a chronic reduction in energy expenditure necessary for thermic regulation processes [26]. (4) Urbanization entails a higher concentration of electrical wiring, wi-fi systems, high-voltage electrical lines causing e-noise. All of those generate electromagnetic fields of different intensities and frequencies. Electromagnetic fields are recently suspected of being a co-factor for the increase of diabetes and obesity in the population [27]. High-voltage electrical lines are more abundant in peripheries rather than downtown area in Milano Metropolitan Area. Main high-voltage electric lines are located in the Northern area of Milano [28].
The second photo shoot, taken during the “first wave” of COVID-19 pandemic indicates a higher incidence of SARS-CoV-2 in the Milano metropolitan Area and in the entire Lombardia region, with respect to the rest of Italy: Chance or necessity? In other words, is it possible that the urbanization per se had caused a higher incidence and worse prognosis of COVID-19? What is the reason of the highest mortality around the world seen in Lombardia region? In large cities, like Milano, population density is higher making difficult social distancing [29]. The second factor conceivably linking urbanization, diabetes and COVID-19 is the oldness of population. Our mapping of the Milano Metropolitan Area clearly shows a positive correlation between 3 indexes involving aging of the population and prevalence of diabetes in different ASSTs (Figs. 2, 3, 4). It is known that older population has the highest mortality rate in all coronavirus and influenza virus outbreaks [9, 17, 30]. Approximately 85% of diabetic patients are obese. In fact, the concomitance of diabetes and aging presumably constitute a synergistic negative factor for the COVID-19 outcome. All authors agree on the fact that diabetic patients have a worse prognosis than non-diabetic ones [17, 31, 32]. The clinical picture of COVID-19 is even worse when obesity is associated with diabetes [9, 33]. Hypertension, cardiovascular disease and COPD have been also called responsible for a most serious prognosis of SARS-CoV2 infection [30, 34]. Therefore, urban diabetes and urban obesity can be suggested as a facilitating factor to reach the high incidence of COVID-19 in Metropolitan Areas worldwide (Milano, Paris, London, New York City, San Paulo, Santiago, Bogota). To note that the 3 months lock-down have determined an increase in obesity prevalence in several countries [35]. Viceversa, adherence to a strict nutritional management and follow-up reduces successfully body weight [36].
Unemployment rate was directly correlated to diabetes prevalence in the Milano metropolitan Area. Intriguingly, unemployment also correlates to susceptibility and mortality in previous influenza epidemics [16, 37]. Conversely, COVID-19 pandemic is causing an increase in suicides among unemployed people [38]. Also low-education level is associated to both a higher prevalence of obesity and diabetes and a lower prognosis of COVID-19 [39, 40].
What are the lessons the health System should learn after COVID-19 outbreak in Milano Metropolitan Area to be put in place during the “second wave “of epidemic? First, diabetes management needs to be optimal even during social distancing. This is to reduce the impact of having a poorly controlled diabetic population during the ongoing”second wave” wave of COVID-19. Secondly, air pollution must be reduced, since it may facilitate the viral diffusion. Finally, territorial medicine should be implemented to prevent, or treat in its initial phase, COVID-19.
The pilot study we presented herein was conducted during the “first wave” of epidemic and works as a “proof of concept” indicating that remote glucose control allows better glycemic control in a condition of social distancing as the lock-down occurred in March and April 2020. Previous studies had shown the possibility of optimizing glucose control via Flash Glucose Monitoring [41, 42], but, at our knowledge, this is the first study utilizing the system during a lock-down (Fig. 7) to bend the “second wave” of contagion.
In conclusion, in January 2020, the casual (the Chance) concomitance of three factors—Urbanization-derived population density/air pollution, diabetes – determined the conditions for an unavoidable (the Necessity, [43]) perfect storm in presence of SARS-CoV2 diffusion. We reported epidemiologic and sociodemographic data in the Milano Metropolitan Area with a picture of the diabetic population taken at the beginning of the SARS-Cov-2 pandemic diffusion. We speculate that the environmental and health conditions of Milano may have favored the high diffusion and the high severity of COVID-19. Population density, pollution, diabetes prevalence, aging index may constitute some clues that need to be further investigated to better understand the high diffusion and mortality rate of COVID-19 in the Milano Metropolitan Area and Lombardia region. We also presented original data showing the efficacy of a Telemedicine Aid during a lock-down period, suggesting that Telemedicine should become more and more a methodology for emergency periods.