An Obesity Paradox - Metabolically Healthy Elderly Obese

It has always been propounded that too much weight is too little in terms of fitness. Obesity is a worldwide health concern affecting children and adults alike. What was once a malady exclusive to the first world has now reached gargantuan proportions and has spread across several countries, worldwide. Of late, the number of elderly obese who are reaching old age is increasing. Besides, research has come up with an obesity paradox – the survival rates from cardiovascular disease (CVD) among the overweight elderly has increased in comparison to their normal weight peers!

There is an undisputed link between obesity and metabolic syndrome (MetS) which is a cluster of conditions including high blood pressure, higher-than-normal blood sugar level, excessive abdominal fat and abnormal cholesterol levels. When these conditions occur together in individuals, it increases a person’s risk of heart disease, stroke and diabetes. Among the obese, the group of individuals who do not suffer from Metabolic syndrome (MetS) are known as “metabolically healthy obese” (MHO).

A cross-sectional study was conducted at the Biocardios Institute of Cardiology, Brasilia, Brazil. In this study, the association of MHO phenotype among those above 80 years with CVD and inflammation was examined. The subjects had to be above the age of 80 years with no clinical evidence of CVD. The study included 208 individuals of 80 years or older, of which 79% were female.

The study population was categorized into four groups - metabolically healthy, normal weight (MHNW); metabolically unhealthy, normal weight (MUNW); MHO (metabolically healthy obese) and metabolically unhealthy obese/overweight (MUHO). Of those studied, 9.0% of men and 14.6% of women were MHO.

For each of these patients, the BMI was calculated and the subjects were categorized into:

• Normal weight - BMI< 25
• Overweight /Obese -BMI equal to or > 25

A person was considered to be have abdominal obesity if the waist size was:

• >88 cm – women
• >102 cm for men.

Physical activity was self reported by the subjects and was scored as a “meets recommendations” or “does not meet recommendations” using WHO’s “Global recommendations on physical activity for health” which suggests adults over the age of 65 do any of the below:

• Moderate-intensity aerobic activity for 150 minutes per week
• Vigorous-intensity aerobic physical activity for 75 minutes per week
• An equivalent combination of both the above mentioned activities

The parameters used to evaluate risk for MetsS are:

• Systolic blood pressure (systolic ≥130 mmHg) and diastolic blood pressure (≥85 mmHg )
• Fasting blood glucose (FBG) ≥110 mg/dL / or individual on diabetes medication
• HDL-C <50 mg/dL in women, <40 mg/dL in men or if the patient was on nicotinic acid
• Triglycerides ≥150 mg/dL or the patient was on fibrates

Individuals were considered metabolically healthy if they had less than two of the above risk factors.

The coronary artery calcium score (CACS) was determined using cardiac CT. If it was equal to 0, then the individual was normal and had no symptoms of subclinical atherosclerosis (CVD).

Relationship between Obesity and Cardio Vascular Disease (CVD)

Obesity is directly linked to cardiovascular diseases (CVD), Type-2 diabetes and hypertension Tot; and all these conditions are characterized by resistance to insulin-mediated glucose disposal (insulin resistance). Not all obese individuals are insulin resistant; however, almost all insulin–resistant individuals tend to be obese. Insulin resistance in obese individuals can be reversed through weight loss yet, not many physicians are into weight-loss counseling and the health care system, too, is not equipped to deal with the consequent disease burden.

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Obese individuals are at a greater risk for atherosclerosis – a condition that is characterized by narrowing of arteries due to accumulation of plaque. Atherosclerosis is a pre-runner to cardiovascular diseases (heart attack, stroke and peripheral vascular disease). However, not all obese individuals are at increased risk for CVD and there is a need to clinically identify those who are at greater risk.

In accordance to the results of the study, the usefulness of traditional risk factors, such as hypertension, need to be re-considered while evaluating the elderly population for the risk of cardiovascular disease. The majority of them have at least one risk factor but what was interesting was that about 11.9% of those studied had a calcium score of CACS = 0 which make them low risk for CVD. This shows that the presence of traditional risk factors alone are not enough to classify this population based on risk. It is suggested that the extent of subclinical CVD be assessed carefully in order to understand disease progression in this group.

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Since the study was a small one, the results need to be confirmed by further studies. Future long- term follow up studies are required to understand the connection between MHO, the progression of cardiovascular disease, and also the morbidity and mortality in this ever- increasing population.

The world has agreed on the fact that it is in the midst of an obesity epidemic. However, public awareness is still wanting when it comes to dealing with issues at hand.

References:

1. The prevalence of the metabolically healthy obese phenotype in an aging population and its association with subclinical cardiovascular disease: The Brazilian study on healthy aging
Lara Roberson1, Sameer Shaharyar2, Ehimen Aneni1, Wladimir Freitas3, Michael Blaha4, Arthur Agatston1, Roger Blumenthal4, Raul D Santos5, Hamid Feiz2, Khurram Nasir1678^* and Andrei Sposito9
Diabetology & Metabolic Syndrome 2014, 6:121

2. http://www.ncbi.nlm.nih.gov/pubmed/21855697

Source-Medindia