The ever-increasing importance of cancer and neurodegenerative diseases continues to grow as populations across the world are affected by death and aging. The vitamin A (RXR) and vitamin D (VDR) receptor pathways offer promising potential to aid in treatment of cancer and Alzheimer’s disease. This thesis discusses the potential application of novel analogs of Bexarotene (RXR agonist), MeTC7 (a new potent VDR antagonist), and vitamin D as possible therapeutics for cancer and Alzheimer’s disease.

Background: Recent studies have shown a decline in birth rates in large metropolitan areas (after accounting for population), which can be possibly explained by barriers to reproduction associated with the COVID-19 pandemic and related lockdowns. Objective: This study’s objective was to investigate the impact of the COVID-19 pandemic and related lockdowns on the fertility rates of women in reproductive ages living in Greater Phoenix. Methods: The total number of inpatient births and people in both Maricopa and Pinal Counties during pre-COVID-19 years (2017-2019) were compared with those during the COVID-19 years (2021) among women in reproductive ages (15-49 years). To make age-specific comparisons, women in reproductive years were divided into eight distinct age group categories (15-17, 18-20, and then five year age group categories to age 49) from which age-specific, general, and total fertility rates were calculated. Results: Using a two-sample z-test for difference in proportions, findings revealed that the general fertility rate in Greater Phoenix had significantly declined from 48 to 46 per 1,000 population from the pre-COVID-19 period to COVID-19 period (P<0.001). Two sample z-tests were also used to compare age-specific fertility rates, which revealed a significant decline in the fertility rate in women ages 15-17 (from 8.0/1000 to 5.0/1000) (P<0.001), 18-20 (from 43.0/1000 to 35.0/1000) (P<0.001), and 21-24 (from 79.0/1000 to 68.0/1000) (P<0.001) from the pre-COVID-19 period to COVID-19 period, while no significant change was observed in the fertility rate in women ages 25-49. Conclusions: The observed general fertility decline in Greater Phoenix as a result of the COVID-19 pandemic poses significant implications for further research on barriers to reproduction brought upon by the COVID-19 pandemic and related lockdown measures. Another direction for further research involves possibly continuing this study to include years 2022 and 2023 in the COVID-19 period, as well as calculating age-specific fertility rates by race.