Obesity in early life induces changes in immune cells that may increase the risk of macular degeneration later in life, a study in mice has found. These changes linger even after weight loss and the restoration of normal metabolism.

Researchers fed mice a diet that promoted weight gain early in life. Then they studied the effects of having excess body fat on the animals' adipose tissue macrophages – a type of immune cell found in fat. Later, they put the mice on a diet that promoted weight loss.

They found that having excess body fat induced epigenetic changes in the macrophages that, in turn, induced an inflammatory response. This pro-inflammatory response persisted even after the mice lost weight. They also found that the macrophages could migrate from the fatty tissue to other parts of the body, including the eyes, where they could contribute to the onset of macular degeneration.

Macular degeneration is the leading cause of blindness worldwide. Having excess body fat is the second leading risk factor for macular degeneration. In fact, a person’s risk of developing macular degeneration increases by 75 percent with each 0.1 increase in their waist-to-hip ratio – a measure of abdominal obesity.

• Read study abstract.