## Sunday, December 13, 2020

### COVID-19 and Vitamin D

Of those with COVID, 80% had vitamin D deficiency. How risky is such a deficiency? Bayesian analysis is appropriate. An excellent short pair of articles on this topic is here: https://www.healthline.com/health-news/new-study-found-80-percent-of-covid-19-patients-were-vitamin-d-deficient This is a good opportunity to use Bayesian statistics to go from the percentage of people who are vitamin D deficient, and have COVID, P(d'|C), to what we want to know, P(C|d'), the risk of having COVID, given that you are deficient in vitamin D. Bayes theorem becomes P(C|d') = P(C) [P(d'|C) / P(d')] These articles note that of those with COVID, 80% were deficient in vitamin D, P(d'|C) = 0.80 The term in brackets is the likelihood factor, the multiplier that converts the general prevalence probabily, P(C), to the probabillty for those who are deficient in vitamin d. The fraction of the nursing home population deficient in vitamin d, P(d'), is P(d')=0.60 https://www.medscape.com/answers/128762-54281/what-is-the-prevalence-of-vitamin-d-deficiency-in-the-us This gives us a likelihood factor of 0.80/0.60= 1.33 elevation of their probability of having COVID from what they would have without a vitamin D deficiency. If P(C) for such a group is 0.05, they are 1.33 times this as likely to contract COVID due to their vitamin D deficiency, about 7%, elevated but far from 80%. Vitamin D is a help, not a cure, not a certain preventative. This review concluded it is not of demonstrated help: https://www.msn.com/en-gb/health/medical/official-review-concludes-lack-of-evidence-linking-vitamin-d-and-lower-covid-risk/ar-BB1c0yW7?appid=hwbrowser&ctype=news

## Saturday, December 5, 2020

### Review of RISE AND CONQUER

In just under one hundred pages, Juan Partida, the author of this highly readable self-help book, encourages, chastises, and advises his readers to remake their lives and fulfill their goals.

I’m up and writing early today, partly due to Partida’s urging, following his good example. I’ve risen; conquering may take a while!

This isn’t a twelve-step program, but five steps to success: determination, accountability, self-gratitude, imperfection, perseverance.

Determination

Partida quotes the cinematic pugilist “Rocky Balboa” to the effect that it is crucial not how many punches you deliver, but how many blows you withstand and keep moving forward.

Toward the end of Rise and Conquer, Partida writes of last century’s Glenn Cunningham’s rise from a near-fatal, crippling childhood injury to Olympic success as a long-distance runner. Talk about determination!

Accountability

If you don’t keep score, it’s tennis without the net. You need to know how you are doing, learn from losses, celebrate your wins. Even little victories stimulate our dopamine. To know what to do and how well you are doing, you need a plan and you need to keep score.

Self-gratitude

Gratitude is an attitude that we all need, appreciating what we have, what we’ve done, what we can still accomplish. Self-love, short of smug conceit, helps get one through the tough spots.

Imperfection

I call myself a “completionist” rather than a “perfectionist.” Most achievements will require tolerating some imperfection, lest you waste your time and energy on trivia. Only the rare individual with exceptional skill might be wise to go for the “perfect” product. There is a reward for such rare outcomes, but usually “the best is the enemy of the good,” as the French saying goes.

Perseverance

The completionist perseveres, knowing that the big pay-off comes from finishing, not from almost-finishing. This relates to a major theme in this enlightening and entertaining book, the true story of the “marshmallow” psychological tests of youngsters for the ability to defer gratification. The kids were each given a marshmallow and told they could eat it now or wait until the investigator returned to the room (delay unspecified) and get a second to eat with the first. The futures of the kids who waited were found to be more successful than those of the kids who did not. Deferring gratification was key.

Deferring consumption, Investing rather than consuming, allows you to take advantage of the power of compound interest. Improving 1% per day means improving not 365% in a year, but rather 37 times! (Exponential growth, not linear.)

Amazon’s Jeff Bezos has become one of the world’s richest men through his planning and persistence. He started, as I recall, selling used books.

Don’t defer your gratification too long, however: get this book. It is inspiring. That’s why I am writing at this early hour, for my benefit and yours.