Combinatorial influence of environmental temperature, obesity and cholesterol on SARS-CoV-2 infectivity.

The continuing evolution of SARS-CoV-2 variants not only causes a long-term global health concerns but also encounters the vaccine/drug effectiveness. The degree of virus infectivity and its clinical outcomes often depend on various biological parameters (e.g., age, genetic factors, diabetes, obesity and other ailments) of an individual along with multiple environmental factors (e.g., air temperature, humidity, seasons). Thus, despite the extensive search for and use of several vaccine/drug candidates, the combinative influence of these various extrinsic and intrinsic risk factors involved in the SARS-CoV-2 virus infectivity has yet to be explored. Previous studies have reported that environment temperature is negatively associated with virus infectivity for SARS-CoV-2. This study elaborates on our previous findings, investigating the link between environmental temperature and other metabolic parameters, such as average total cholesterol and obesity, with the increase in COVID-19 cases. Statistical analysis conducted on a per country basis not only supports the existence of a significant negative correlation between environmental temperature and SARS-CoV-2 infections but also found a strong positive correlation between COVID-19 cases and these metabolic parameters. In addition, a multiphase growth curve model (GCM) was built to predict the contribution of these covariates in SARS-CoV-2 infectivity. These findings, for first time, support the idea that there might be a combinatorial impact of environmental temperature, average total cholesterol, and obesity in the inflation of the SARS-CoV-2 infectivity.

Colder environments are associated with a greater cancer incidence in the female population of the United States.

Cancer incidence and/or mortality among individuals varies with diet, socio-culture, ethnicity, race, gender, and age. Similarly, environmental temperature modulates many biological functions. To study the effect of environment temperature on cancer incidence, the US population was selected. Because, county-wise cancer incidence rate data of various anatomical site-specific cancers and different races/ethnicities for both males and females are available. Moreover, the differences amongst the aforementioned factors among individuals are much less, as compared to the world population. Statistical analysis showed a negative correlation between the average annual temperature and cancer incidence rate at all anatomical sites and individually for 13 types (out of 16 types) of anatomical site-specific cancer incidence rates (e.g. uterine, bladder, thyroid, breast, esophagus, ovary, melanoma, non-Hodgkin lymphoma, leukemia, brain, pancreas, etc.) for females. Further analysis found a similar inverse trend in all races/ethnicities of the female population but not in all male races/ethnicities or anatomical site-specific cancers. Moreover, the majority of the counties having the top-most cancer incidence rate in females are located above the latitude 36.5°N. These findings indicate that living in a cold county in the United States might have a higher risk of cancer irrespective of cancer type (except cervical and liver) and races/ethnicities for females but not in all such cases for the male population.

Is cholesterol a mediator of cold-induced cancer?

Many factors such as smoking, obesity, and high fat have been either directly or indirectly linked to cancer deaths and/or incidences. Similarly, abnormal serum cholesterol levels have been assigned as a risk factor for cancer, but some studies show a discrepant result. To resolve this discrepancy, we have analyzed cholesterol data of 166 countries. Univariate analysis showed a positive correlation between serum average total cholesterol (ATC) and overall cancer mortality rate (CMR) [tau = 0.277, z = 5.19, p < 0.0001]. It was also observed that a similar positive correlation was found between ATC and different anatomical site-specific CMRs in lung, bladder, ovarian, breast, and pancreatic cancers. Our recent published data documented an existence of a negative correlation between average annual temperature (AAT) and overall CMR, as well as CMR of the abovementioned anatomical site-specific cancers. Statistical analysis further shows a negative correlation between AAT and ATC, similar to that of AAT and CMR. The resulting patterns of univariate analysis between AAT and CMR are almost identical with AAT and ATC, when this analysis was performed every 2 °C of AAT increment for all countries. Moreover, geographical location of the top 50 countries having the highest CMR is almost similar to the top 50 countries having the highest ATC. Similarly, the least 50 countries having the lowest CMR are located in the same geographical region, similar to the least 50 countries having the lowest ATC. These data along with other literature reports suggest that cholesterol could be a mediator of cold-induced cancer mortality.