January Newsletter
In This Issue
Don't Be Deficient
Not Just For Knees
Canadian Fit
A Better Model of Medical Care
Old-fashioned medicine with 21st Century convenience and technology
Quick Links
Join Our List
View my profile on LinkedIn 
Follow me on Twitter
Welcome to the January newsletter. The goal of this newsletter is to provide information and analysis of timely topics from recent articles published in the  medical literature. I hope you find this information useful and helpful in your health journey.   
COVID-19 continues to dominate our lives. Here in Wisconsin we are doing better with cases, hospitalizations, and deaths trending downward. We have two incredibly effective vaccines out and we are in the early stages of a massive vaccination program. Compliance with the strategies recommended by the CDC and others is good but is there anything else we can do to protect ourselves until we get large numbers of our population vaccinated? The first paper this month suggests that a simple vitamin may have remarkable effects on protection from COVID-19. 

The second study examines some interesting findings around another common supplement many people use for arthritis. Could this supplement also reduce our risk of cardiovascular and all-cause mortality? Read on to find out which supplements could be useful and a possible mechanism of action. 

I know some of my patients have returned to the gym, at least some of the time. This pandemic has put a new emphasis on our home exercise routines. We reviewed some of these in the  November newsletter and this month I came across a study using a bit of a different pattern of exercise than I covered before. This Canadian style workout may be another way to mix it up when you are EFH (exercising from home). 
Information regarding COVID-19 is constantly changing. Since last month we have had two vaccines approved for use here in the United States and more are in the pipeline. The currently available vaccines are incredibly effective (over 99.95% a few weeks after the second dose) and look to be truly game changers. They have been given to around 30 million people with good safety. The incidence of anaphylaxis is 2.5/1 million doses, not quite 1 in a million but close. When you have a chance to get vaccinated, I highly recommend it. 

If you are feeling sick or concerned about symptoms, please call me first. We can discuss your symptoms and decide the best course of action for you, including testing. I have saliva based COVID-19 PCR tests available in my office with 24+ hour turnaround. Serum antibody tests can be performed as well with 24-hour turnaround. Please continue to wash your hands frequently, avoid touching your face, and avoid going out if you are sick.   
Don't Be Deficient
Vitamin D deficiency more likely to be positive for COVID-19
vitamin D
As the COVID-19 pandemic has continued we are all looking for ways to avoid becoming infected. This study examined the association between vitamin D deficiency and COVID-19. As compared to people who were not vitamin D deficient, those with vitamin d deficiency were 4.6 times more likely to be positive for COVID-19. After adjusting for age, people with a vitamin D deficiency were overall 5 times more likely to develop a COVID-19 infection. 

  • Objective: The 2019 coronavirus disease (COVID-19) pandemic has disproportionally affected a variety of patients with underlying risk factors such as respiratory and cardiovascular diseases, diabetes, obesity, and black race. Vitamin D deficiency, which can result in a compromised immune response, has been also linked to increased risk and increased morbidities associated with COVID-19. In the absence of large-scale longitudinal studies to determine the strength of association between vitamin deficiency and COVID-19, cross-sectional studies of large patient cohorts can be used.
  • Methods: We used the i2b2 patient's registry platform at the University of Florida Health Center to generate a count of patients using the international classification of diseases (ICD)-10 diagnosis codes for the period of October 1, 2015, through June 30, 2020. Logistic regression of the aggregates was used for the analysis.
  • Results: Patients with vitamin D deficiency were 4.6 times more likely to be positive for COVID-19 (indicated by the ICD-10 diagnostic code COVID19) than patients with no deficiency (P < 0.001). The association decreased slightly after adjusting for sex (odds ratio [OR] = 4.58; P < 0.001) and malabsorption (OR = 4.46; P < 0.001), respectively. The association decreased significantly but remained robust (P < 0.001) after adjusting for race (OR = 3.76; P < 0.001), periodontal disease status (OR = 3.64; P < 0.001), diabetes (OR = 3.28; P < 0.001), and obesity (OR = 2.27; P < 0.001), respectively. In addition, patients with vitamin D deficiency were 5 times more likely to be infected with COVID-19 than patients with no deficiency after adjusting for age groups (OR = 5.155; P < 0.001).
  • Conclusions: Vitamin D deficiency is significantly associated with increased risk for COVID-19.

Vitamin D is not a traditional vitamin. Low levels of vitamin D can increase the likelihood of developing multiple acute and chronic ailments including cardiovascular and autoimmune diseases, diabetes, cancer, infectious diseases, and periodontal disease. In most people, more than 80% of vitamin D is formed in the skin after exposure to sunlight so low vitamin D usually reflects deficient sunlight exposure, deficient dietary intake, or both. This study was a data review of medical records that found a strong link between vitamin D deficiency and COVID-19 infection. There have been other studies suggesting low vitamin D levels may be associated with worsened cytokine storm (the cause of severe COVID-19 outcomes) and overall increased risk of respiratory infections. This study simply looked at positive COVID tests. They found that low vitamin D increased the risk of testing positive for COVID-19 by a factor of 5. Most of the subjects were also African-American which is a population that often has low vitamin D levels and has been hit especially hard by this pandemic both in number of cases and severity of outcomes. 

While we can't determine causation versus correlation from this type of study, multiple studies are showing a correlation between low vitamin D levels and COVID-19 diagnosis and worsened outcomes. It makes sense to be to supplement with vitamin D during this time. There is no significant risk to this practice and there are possible positive outcomes. I am recommending 5000 IU/day intake for most people. This is a level that will avoid any possible toxicity and will get the majority of people out of a possible deficient state. I generally recommend a capsule or gel-cap formula for better absorption. 
Not Just For Knees
Can glucosamine/chondroitin reduce mortality? 

Glucosamine and chondroitin are widely used supplements containing natural compounds found in cartilage and are taken as a dietary supplement to treat osteoarthritis and joint pain. There have been some recent studies suggesting possible benefits outside of joint pain involving long-term mortality. This study set out to investigate this relationship using data from the National Health and Nutrition Examination Survey (NHANES), a nationally representative cross-sectional survey conducted by National Center for Health Statistics (NCHS). This survey has been collecting data on participants' use of dietary supplements. 

This study showed a strong association between regular intake of glucosamine/chondroitin and overall and cardiovascular mortality. Compared with nonusers, respondents taking glucosamine/chondroitin were about 49% less likely to experience cardiovascular mortality. While controlling for age, glucosamine/chondroitin use was associated with a 39% reduction and 65% reduction in all-cause and cardiovascular mortality respectively. Further analysis showed that the association was maintained after adjustment for age, gender, race, education, smoking status, and physical activity.


  • Background: Limited previous studies in the United Kingdom or a single US state have demonstrated an association between intake of glucosamine/chondroitin and mortality. This study sought to investigate the association between regular consumption of glucosamine/chondroitin and overall and cardiovascular (CVD) mortality in a national sample of US adults.
  • Methods: Combined data from 16,686 participants in National Health and Nutrition Examination Survey 1999 to 2010, merged with the 2015 Public-use Linked Mortality File. Cox proportional hazards models were conducted for both CVD and all-cause mortality.
  • Results: In the study sample, there were 658 (3.94%) participants who had been taking glucosamine/chondroitin for a year or longer. During followup (median, 107 months), there were 3366 total deaths (20.17%); 674 (20.02%) were due to CVD. Respondents taking glucosamine/chondroitin were less likely to have CVD mortality (hazard ratio [HR] = 0.51; 95% CI, 0.28-0.92). After controlling for age, use was associated with a 39% reduction in all-cause (HR = 0.61; 95% CI, 0.49-0.77) and 65% reduction (HR = 0.35; 95% CI, 0.20-0.61) in CVD mortality. Multivariable-adjusted HR showed that the association was maintained after adjustment for age, sex, race, education, smoking status, and physical activity (all-cause mortality, HR = 0.73; 95% CI, 0.57-0.93; CVD mortality, HR = 0.42; 95% CI, 0.23-0.75).
  • Conclusions: Regular intake of glucosamine/chondroitin is associated with lower all-cause and CVD mortality in a national US cohort and the findings are consistent with previous studies in other populations. Prospective studies to confirm the link may be warranted.

I found this is an interesting study because of the dramatic numbers. This is another study that we have to think about correlation versus causation. The number of subjects in the study taking glucosamine/chondroitin was small (< 4%) so it makes it more difficult to draw conclusions from the study. However, the numbers obtained are quite compelling. There are not many things that potentially reduce overall cardiovascular mortality by almost 50%! Additionally, the numbers from this study were similar to other studies from both the US and UK. All these were cohort population studies so not the strongest form of data. Certainly, a randomized, placebo-controlled study would be great to have to examine this relationship further. 

The conclusions from these studies do make some physiological sense in my mind. One of the big causes of mortality and heart disease is inflammation. Others have found c-reactive protein levels (an inflammatory marker) were lower in people taking glucosamine and chondroitin which suggests a systemic anti-inflammatory effect. Inflammation and cytokine effects have been suggested as one of the possible mechanisms for the effects of glucosamine and chondroitin on mortality. While this study is a correlation not causation study, the findings are quite compelling in the viewpoint of cardiovascular mortality and overall mortality reduction. 

If you choose to try glucosamine/chondroitin I recommend using a good quality supplement. I generally recommend glucosamine-sulfate over glucosamine-HCl as studies have shown this to be more effective in the setting of arthritis. This study doesn't specify the dosages of the supplements. The usual recommendations for arthritis are 1500 mg glucosamine and 1200 mg of chondroitin daily, generally in divided doses. 

Canadian Fit
Canadian military bodyweight training program improves fitness
We have been discussing options for times when we haven't been able to use the gym. There are a lot of home programs out there and I highlighted some of these previously here. I came across this study and thought it was interesting. It's modeled after the Canadian military's 5BX program which stands for 'Five Basic Exercises' which was developed back in the 1950s for the Royal Canadian Air Force. It requires no equipment and can be adjusted to individual fitness levels. The focus is calisthenics such as running in place, modified burpees, and squat jumps. Participants performed these exercises interspersed with light active recovery periods. The 11-minute routine, which included a brief warm-up, does not demand high levels of motivation or "all-out" efforts. After six weeks of training, three times per week, cardiorespiratory fitness was higher among those who followed the program, compared with those who didn't. This program could be a time-efficient, practical, and effective approach to maintain fitness when no gym or equipment is available. 


  • Bodyweight training (BWT) is a style of interval exercise based on classic principles of physical education. Limited research, however, has examined the efficacy of BWT on cardiorespiratory fitness. This is especially true for simple BWT protocols that do not require extraordinarily high levels of effort. We examined the effect of a BWT protocol, modeled after the original "Five Basic Exercises" (5BX) plan, on peak oxygen uptake (VO2peak) in healthy, inactive adults (20 ± 1 y; body mass index: 20 ± 5 kg/m2; mean ± SD). Participants were randomized to a training group that performed 18 sessions over six weeks (n=9), or a non-training control group (n = 10). The 11-minute session involved five exercises (burpees, high knees, split squat jumps, high knees, squat jumps), each performed for 60-seconds at a self-selected "challenging" pace, interspersed with active recovery periods (walking). Mean intensity during training was 82 ± 5% of maximal heart rate, rating of perceived exertion was 14 ± 3 out of 20, and compliance was 100%. ANCOVA revealed a significant difference between groups after the intervention, such that VO2peak was higher in the training group compared to control (34.2 ± 6.4 vs 30.3 ± 11.1 ml/kg/min; p = 0.03). Peak power output during the VO2peak test was also higher after training compared to control (211 ± 43 vs 191 ±50 W, p = 0.004). There were no changes in leg muscular endurance, handgrip strength or vertical jump height in either group. We conclude that simple BWT- requiring minimal time commitment and no specialized equipment - can enhance cardiorespiratory fitness in inactive adults. These findings have relevance for individuals seeking practical, time-efficient approaches to exercise.
This study looked at a simple variation of HIIT (high-intensity interval training) which is done at a challenging effort and is easily modified per individual needs and fitness levels. 

For each bout of vigorous exercise, participants self-selected a relative intensity or effort level based on instructions to choose a "challenging pace", with the goal of completing as many repetitions as possible during each interval.

Specifics of the study program: 
Warm-up: 1-minute of jumping jacks; 
Vigorous exercise: 1-minute of modified burpees without push-ups; 
Recovery: 1-minute of walking in place; 
Vigorous exercise: 1-minute of high knee running in place; 
Recovery: 1-minute of walking in place; 
Vigorous exercise: 1-minute of split squat jumps; 
Recovery: 1-minute of walking in place; 
Vigorous exercise: 1-minute of high knee running in place; 
Recovery: 1-minute of walking in place; 
Vigorous exercise: 1-minute of squat jumps; 
Cool-down: 1-minute of walking in place.

This program is different than the classic 5BX program which has several stages and exercises people work through as they get more fit. I think the exercises used in the study program is good for people who have some exercise experience and is pretty equivalent to the more advanced levels of the classic program. I think you can substitute other exercises into the pattern of vigorous exercise for 1 minute followed by 1 minute of recovery and have another workout that could be used for your home exercise routine and mixed in with other Tabata and HIIT type routines for increased variety. 

Below is a video of a Canadian woman doing the lower level classic routine in her garage. Bonus for the home hockey net in the shot. 

Royal Canadian Air Force 5BX Workout - try it with me!
Royal Canadian Air Force 5BX Workout - try it with me!

Thank you for taking the time to read through this newsletter. I hope you have found this information useful as we work together to optimize your health. Feel free to pass this on to anyone you think would benefit from this information. 

You can find previous newsletters archived on my website here


As always, if you have questions about anything in this newsletter or have topics you would like me to address, please feel free to contact me by email, phone, or just stop by! 

To Your Good Health,
Mark Niedfeldt, M.D.