Improved Survival in ALS Patients with Mild Obesity
The study of over 400 ALS patients conducted at Massachusetts General Hospital has shown that mildly obese patients survived longer compared to patients with normal weight, or those underweight or overweight. This is an exception to the rule that obesity is a health hazard.
The studies conducted earlier on animal models demonstrated that increase in weight prolonged survival. Now, the scientists aimed to discover how cholesterol levels influence survival. They found out that patients with different body mass index (a measure of weight adjusted for height) varied in terms of survival. Patients with BMI equal to 30 through 35 who are considered mildly obese survived the longest; the second longest survivals were overweight patients with BMI of 25 to 30.
Since the previous smaller study showed that patients with higher proportion of low-density lipoprotein (LDL) to high-density lipoprotein (HDL) might survive longer, the research team aimed to test this hypothesis on a larger number of patients. They turned to analyze data on over 400 ALS patients who had earlier participated in clinical trials of medicines for ALS treatment
. For each of the participants, the researchers had results of blood test taken before the trials and survival in the range of one to two years (how long the patients survived without mechanical ventilation).
The study has shown that malnourished or extremely obese patients survived the shortest, while mildly obese patients were the leaders in survival. The researchers attribute this fact to higher energy reserves in these patients. Since ALS patients lose more weight that can be caused by muscle mass loss, having such reserves seem to play an important role in survival in ALS patients.
Based on this finding, the researchers are conducting a clinical trial of the safety and tolerability of diet high in fat and calories for ALS patients. To better control calory and fat intake, the study covers only the patients already having a feeding tube.