A recent report report from the Center for Infectious Disease Research and Policy indicates that 25% of hospitalized H1N1 victims in a California study were morbidly obese versus 4% of the US population and more than half were obese. It did not collect data on whether the heavy patients had other underlying conditions although the analysis found that probable. Now the question is, is obesity an independent risk factor or a proxy for other conditions that make flu infection worse?
The problem with correlations is that they tend to label clusters of risk factors with one cause. Obesity often is associated with conditions that can worsen the flu. And people can be relatively healthy although fat if they lower their blood insulin levels, triglycerides and are active. However the proportion of fat people who exercise regularly, eat well and keep their blood parameters in good shape is not high.
Still it is not easily apparent that obesity would be a major factor in flu deaths. What then accounts for the correlation? Here are insights from Chinese and western medicine:
- Carrying extra weight can make the lungs and heart work harder to oxygenate and circulate the blood, causing stagnation. Regular exercise can diminish this effect which is why it is essential for heavy people to move.
- We know that a high proportion of heavy people have elevated blood sugar and blood insulin. We also know that sugar, which is energetically cooling and damp, feeds infection.
- Food allergies are often related to obesity, providing an underlying inflammation. In Chinese medicine terms, food allergies come from damp foods that overwhelm Spleen qi and increase Phlegm Heat or Phlegm Damp. Phlegm will increase flu susceptibility.
- In Chinese medicine, fat itself is seen as a form of pathological Phlegm. Phlegm is a factor in respiratory illnesses, and can also stagnate or block the Wei (deffensive, immune) qi.
- Poor Lung function then can cause the formation of Phlegm fat as well as being susceptible to respiratory disease.
- Adenoviruses (respiratory viruses) can make people (and mice) fat. Infectobesity is real and is associated with deficient Lung and Wei qi, the protective immune factors in our body.
- Asthma as an underlying disease can cause obesity if it is allowed to diminish exercise. This is seen as a Phlegm condition as well.
- Obesity can be caused by insufficient sleep, which also diminishes our immune system. Obesity contributes to obstructive sleep apnea which diminishes the ability to get sleep and deoxygenates the blood.
- Obesity is a significant side effect for steroid use associated with a variety of other diseases such as autoimmune conditions which increase flu susceptibility. It is also a significant side effect of a variety of other medications.
- Poverty is associated with obesity, and is also associated with low access to good medical care. In fact disease often precipitates poverty and poverty poor diet and low immune status.
- Endocrine disruptors in plastics, pthlates, pesticides and other compounds have been shown to increase obesity, and are certainly bad for the immune system.
- Obese people have much lower Vitamin D levels than in the population and Vitamin D has been shown to reduce flu infection. The reasons vary from lower sun exposure due to reluctance to expose skin, lower skin area to produce Vitamin D compared to internal body area, more gallbladder removal which makes fat soluble vitamins difficult to assimilate, hypoparathyroidism and factors we may not yet have identified. Obese people may need to take 50,000 iu daily (with monitoring) just to maintain levels.
Autopsies on people with the Swine Flu show viral levels in the lungs a hundredfold higher than in normal flu deaths. Lung strength is imperative. Since obesity tends to be fairly intractable, it is essential to move, to sleep, to eat well and to raise Vitamin D levels in order to stay as healthy as possible during the flu season. You can be fat and fit, but it takes an effort. But that effort may pay off with improved immune function and resistance to the flu.
Louie JK, Acosta M, Winter K, et al. Factors associated with death or hospitalization due to pandemic 2009 influenza A (H1N1) in California. JAMA 2009 Nov 4;302(17):1896-1902 [Abstract] Schnirring, Lisa. Obesity risk stands out in study of California’s sickest H1N1 patients. CIDRAP 11/2/09