Obesity Does Not Increase Risk for Anemia

Readers of these pages probably recall that obesity is commonly associated with increased markers of inflammation. It is now, therefore, often referred to as a state of chronic low-grade inflammation. Chronic inflammation is commonly associated with anemia even in the presence of adequate iron stores. So is obesity associated with an increased risk for anemia?

This question was addressed by Karlee Ausk and George Ioannou from the University of Washington, Seattle, WA in participants of the third National Health and Nutrition Examination Survey (NHANES III) by analysing the relationship between BMI and features of anemia of chronic disease, including low hemoglobin concentration, low serum iron and transferrin saturation (TS), and elevated serum ferritin (OBESITY).

After adjustment for age, gender, menstruation, race/ethnicity, education, alcohol consumption, smoking, blood donation, and dietary iron intake, serum ferritin was progressively higher with increasing BMI category, whereas serum iron and TS were progressively lower.

However, compared to normal-weight persons, those in all other higher BMI categories did not have a significant change in hemoglobin concentration after adjustment for the above-mentioned confounders.

Overweight and obesity were associated with changes in serum iron, TS, and ferritin that would be expected to occur in the setting of chronic, systemic inflammation. However, overweight and obese persons were not more likely to be anemic compared with normal-weight persons.

How individuals with obesity maintain normal hemoglobin levels despite these elevated markers of chronic inflammation and changes in iron parameters is not clear.

Nevertheless, given the rather high prevalence of anemia in general, work up for these parameters should probably be included in the work up of all individuals with obesity, who are at risk for or present with signs of anemia. This is particularly true for patients, who have undergone bariatric surgery or are on particularly restrictive diets.

Edmonton, Alberta