1700 words

Strength differences between the races are of big interest to me. Not only due to the evolutionary perspective, but also due to how it relates to health and disease. Hand grip strength (HGS) in men is a good predictor of: Parkinson’s disease (Roberts et al, 2015); lower cardiovascular health profile (Lawman et al, 2016); Alzheimer’s disease (Buchman et al, 2007) and other chronic diseases in men, not in women (Cheung et al, 2013). HGS also predicts diabetes and hypertension (Mainous 3rd et al, 2015), as well as death from all causes, cardiovascular disease (CVD) and cancer in men (Gale et al, 2006). Due to these associations, the study of HGS in men is well warranted. However, here too, we find racial differences and they just so happen to follow trends and corroborate with other data on the mortality of men with lower grip strength.

Araujo et al (2010) obtained data from the Boston Community Health/Bone (BACH/Bone) Survey which included 1,219 randomly selected black, white and ‘Hispanic’ men to assess lean mass, muscle strength, and physical function. Though out of this sample, 10 men didn’t have a DXA performed and 49 men missing data on lean mass, fat mass and Physical Activity for the Elderly (PASE), which left 1,157 men to be analyzed. These studies, however, leave a lot to be desired in how they measure strength (for the purposes that I’m interested in) but they will have to do, for now. Unlike the bench pressing study I wrote about yesterday in which calipers were used to assess body fat, in this study they measured body fat with the DXA scan to assess lean mass. That way, there won’t be any potential confounds, possibly skewing lean mass/fat comparisons. The age of the cohort ranged from 30 to 79 with a mean age of 48.

Table 1 shows the results of the DXA scan, anthropometric data and lean and fat mass. Blacks’ mean lean mass of 124 pounds (mean weight 193 pounds), ‘Hispanics” lean mass was 114 pounds (mean weight 179 pounds) and whites had a mean lean mass of 122 pounds (mean weight 196 pounds). Blacks had a mean grip strength of 89.826 pounds while ‘Hispanics’ had a mean grip strength of 82.698 pounds and whites had a mean grip strength of 88.528 pounds. Blacks had a higher lean mass index than whites by 5 percent, but had a composite physical function score 20 percent lower than whites.

White men had a 25 percent higher average composite physical functioning score, which, when indexed by lean mass and grip, white men had grips 10 percent stronger. White men also scored higher on physical function and lean mass. White men had lower levels of lean muscle mass than blacks and ‘Hispanics’ after controlling for confounding factors, yet whites were still stronger. Since lean mass is related to strength, blacks and ‘Hispanics’ should have had a stronger grip, yet they didn’t. Why?

The authors stated that the reason was unknown since they didn’t test for muscle quality or strength exerted for each unit of muscle. I have proven that whites, on average, are stronger than blacks. If the it were true that blacks were stronger, which is what you see upon first glance viewing table 1 of Araujo et al (2010), then the black population would have lower rates of morbidity and mortality due to higher levels of strength. The black population doesn’t have lower levels of morbidity or mortality. Therefore blacks are not stronger than whites.

Muscular strength is associated with mortality in men (Ruiz et al, 2008; Volaklis, Halle, and Meisenger, 2015), so if the strongest race of men has lower incidences of the above diseases mentioned above along with a higher life expectancy, then there is a good chance that muscular strength is a good predictor of disease within and between race and ethnicity as well. Muscular strength is inversely associated with death from all causes and cancer in men even after adjusting for cardiorespiratory factors. The findings from Ruiz et al (2008) are valid for young and old men (aged 20-82), as well as normal and overweight men.

There are clear associations between muscular strength/hand grip strength and mortality. These differences in mortality are also seen in the United States between race. In 2012, the death rate for all cancer combined was 24 percent higher in black men than in white men. Life expectancy is lower for blacks at 72.3 years compared to 76.7 years for white men (American Cancer Society, 2016). As shown above, men with lower levels of muscular strength have a higher risk of mortality.

As I have asserted in the past, blacks have differing muscle fiber typing (type II) on average when compared to whites (who have type I fibers). Type II muscle fibers are associated with a reduced Vo2 max, which has implications for the health of black Americans. Blacks have lower aerobic capacity along with a greater percentage of type II skeletal muscle fiber (Caesar and Hunter, 2015).

Slow twitch fibers fire through aerobic pathways. Fast twitch (Type II) fibers fire through anaerobic pathways and tire quicker than slow twitch. Each fiber fires off through different pathways, whether they be anaerobic or aerobic. The body uses two types of energy systems, aerobic or anaerobic, which then generate Adenosine Triphosphate, better known as ATP, which causes the muscles to contract or relax. Depending on the type of fibers an individual has dictates which pathway muscles use to contract which then, ultimately, dictate if there is high muscular endurance or if the fibers will fire off faster for more speed.

Differences in muscle fiber typing explain why whites had a stronger grip than non-whites in the BACH/Bone survey. Testing the fiber typings of the three ethnies would have found a higher percentage of type II fibers in blacks, which would account for the lower grip strength despite having higher levels of lean mass when compared to whites.

The apparent ‘paradox’ seen in Araujo et al (2010) is explained by basic physiology. However, in our politically correct society, such differences may be suppressed and thusly people won’t be able to receive the help they need. Race is an extremely useful marker in regards to medicine. By denying average racial differences in numerous anatomical/metabolic/physiologic traits, we deny people the right help they need. Common sense dictates that if such relationships are found, then further research must occur in order to find the cause and a possible solution to the problem.

This study by Araujo et al shows that we need to pay more attention to race when it comes to disease. By denying racial differences we are dooming people to a lower quality of life due to the implicit assumption that we are all the same on the inside (farrrrr from the truth). These average differences in metabolism, anatomy, and physiology do account for some of the variation in disease between race and ethnicity, so this warrants further research. If only we, as a country, can acknowledge racial differences and get people the correct help. Maybe one day we can stop assuming that all races are equal on the inside and when you notice a trend within a particular racial group you find out the cause and whether or not there is any way to ameliorate it.

Muscular strength adds to the protective effect of cardiorespiratory fitness and risk of death in men. That blacks have lower levels of strength than whites, have different muscle fiber typing than whites on average, a lower life expectancy than whites, and higher rates of cancer show that they do not have the physical strength that whites do. What really seals the deal is the fact that blacks have more type II muscle fibers (Caesar and Hunter, 2015). Muscular strength/grip strength is a great predictor of disease in men. Since blacks have lower grip strength yet higher levels of lean mass compared to whites, this show that the difference is due to muscle fiber typing, which, as I have covered in the past, are also associated with cardiometabolic disease and obesity.

Blacks have the highest rate of obesity in America. Looking at obesity rates in America, we see that 69 percent of black men are overweight or obese (remember that black Americans with more African ancestry are less likely to be obese), 71.4 percent of white men are overweight or obese, and 78.6 percent of ‘Hispanic’ men are overweight or obese (Ogden et al, 2016).

Blacks are not stronger than whites. I have compiled enough data to prove that fact. This adds further support for my contention.

References

American Cancer Society. Cancer Facts & Figures for African Americans 2016-2018. Atlanta: American Cancer Society, 2016.

Araujo, A. B., Chiu, G. R., Kupelian, V., Hall, S. A., Williams, R. E., Clark, R. V., & Mckinlay, J. B. (2010). Lean mass, muscle strength, and physical function in a diverse population of men: a population-based cross-sectional study. BMC Public Health,10(1). doi:10.1186/1471-2458-10-508

Buchman, A. S., Wilson, R. S., Boyle, P. A., Bienias, J. L., & Bennett, D. A. (2007). Grip Strength and the Risk of Incident Alzheimer’s Disease. Neuroepidemiology,29(1-2), 66-73. doi:10.1159/000109498

Ceaser, T., & Hunter, G. (2015). Black and White Race Differences in Aerobic Capacity, Muscle Fiber Type, and Their Influence on Metabolic Processes. Sports Medicine,45(5), 615-623. doi:10.1007/s40279-015-0318-7

Cheung, C., Nguyen, U. D., Au, E., Tan, K. C., & Kung, A. W. (2013). Association of handgrip strength with chronic diseases and multimorbidity. Age,35(3), 929-941. doi:10.1007/s11357-012-9385-y

Gale, C. R., Martyn, C. N., Cooper, C., & Sayer, A. A. (2006). Grip strength, body composition, and mortality. International Journal of Epidemiology,36(1), 228-235. doi:10.1093/ije/dyl224

Lawman, H. G., Troiano, R. P., Perna, F. M., Wang, C., Fryar, C. D., & Ogden, C. L. (2016). Associations of Relative Handgrip Strength and Cardiovascular Disease Biomarkers in U.S. Adults, 2011–2012. American Journal of Preventive Medicine,50(6), 677-683. doi:10.1016/j.amepre.2015.10.022

Mainous, A. G., Tanner, R. J., Anton, S. D., & Jo, A. (2015). Grip Strength as a Marker of Hypertension and Diabetes in Healthy Weight Adults. American Journal of Preventive Medicine,49(6), 850-858. doi:10.1016/j.amepre.2015.05.025

Ogden C. L., Carroll, M. D., Lawman, H. G., Fryar, C. D., Kruszon-Moran, D., Kit, B.K., & Flegal K. M. (2016). Trends in obesity prevalence among children and adolescents in the United States, 1988-1994 through 2013-2014. JAMA, 315(21), 2292-2299.

Roberts, H. C., Syddall, H. E., Butchart, J. W., Stack, E. L., Cooper, C., & Sayer, A. A. (2015). The Association of Grip Strength With Severity and Duration of Parkinson’s. Neurorehabilitation and Neural Repair,29(9), 889-896. doi:10.1177/1545968315570324

Ruiz, J. R., Sui, X., Lobelo, F., Morrow, J. R., Jackson, A. W., Sjostrom, M., & Blair, S. N. (2008). Association between muscular strength and mortality in men: prospective cohort study. Bmj,337(Jul01 2). doi:10.1136/bmj.a439

Volaklis, K. A., Halle, M., & Meisinger, C. (2015). Muscular strength as a strong predictor of mortality: A narrative review. European Journal of Internal Medicine,26(5), 303-310. doi:10.1016/j.ejim.2015.04.013