The Chinese Famine of 1959-61 has been widely interpreted as important to later epidemics of Type 2 Diabetes Mellitus (T2DM), but in re-examining 17 related Chinese studies researchers at Columbia University Mailman School of Public Health and Leiden Medical Center, found little evidence for this association. Findings are in Nature Reviews Endocrinology.
“Most Chinese studies were limited in using appropriate age-balanced controls,” said Dr. L.H. Lumey, professor of epidemiology at Columbia Mailman. “Therefore, establishing a firm connection between prenatal famine and T2DM in future studies in China will require significant improvements in study design and execution.”
To demonstrate limitations, the researchers re-analyzed the data using several control groups. With age-balanced controls, no increases were seen in T2DM.
Dr. Lumey and colleagues further determined that studying just pre-famine births as controls could suggest a “protective” effect of famine on later health outcomes. Studies from both the Dutch and the Chinese Famines show that increased body size in adulthood has important implications for T2DM after prenatal famine exposure. Yet the studies have not yet examined if changes in DNA methylation are large enough to explain the increased obesity and hyperglycemia in China today.
Because of limitations in study design and the original analyses of the Chinese studies it is an open question if the famine has significantly contributed to the current epidemic in China or has a long-term impact.
“The current T2DM epidemic in China is an enormous public health challenge,” noted Dr. Lumey. “Public health efforts should focus now on well-established risk factors for overweight and obesity, especially the increased intake of energy dense foods and sedentary lifestyles.”Tags: Friday Letter Submission