People who sometimes went hungry as children had slower cognitive decline once they were elderly than people who always had enough food to eat, according to a new study published in the December 11, 2012, print issue of Neurology, the medical journal of the American Academy of Neurology.
"These results were unexpected because other studies have shown that people who experience adversity as children are more likely to have problems such as heart disease, mental illness and even lower cognitive functioning than people whose childhoods are free of adversity," said study author Lisa L. Barnes, PhD, of Rush University Medical Center in Chicago.
The study involved 6,158 people with an average age of 75 who were living in Chicago. Participants, 62 percent of whom were African American, were asked about their health as children, their family's financial situation, and their home learning environment, based on how often others read or told them stories or played games with them. Then every three years for up to 16 years, participants took cognitive tests to measure any changes.
For the African American participants, the 5.8 percent who reported that they went without enough food to eat sometimes, often or always were more likely to have a slower rate of cognitive decline, or decline that was reduced by about one-third, than those who rarely or never went without enough food to eat. The 8.4 percent of African American participants who reported that they were much thinner at age 12 than other kids their age also were more likely to have a slower rate of cognitive decline, also by one-third, than those who said they were about the same size or heavier than other kids their age. For Caucasians, there was no relationship between any of the childhood adversity factors and cognitive decline.
Barnes said researchers aren't sure why childhood hunger could have a possible protective effect on cognitive decline. One potential explanation for the finding could be found in research that has shown that calorie restriction can delay the onset of age-related changes in the body and increase the life span. Another explanation could be a selective survival effect. The older people in the study who experienced childhood adversity may be the hardiest and most resilient of their era; those with the most extreme adversity may have died before they reached old age.
Barnes noted that the results stayed the same after researchers adjusted for factors such as amount of education and health problems. The results also did not change after researchers repeated the analysis after excluding people with the lowest cognitive function at the beginning of the study to help rule out the possibility that people with mild, undiagnosed Alzheimer's disease were included in the study.
Because relatively few Caucasians in the study reported childhood adversity, the study may not have been able to detect an effect of adversity on cognitive decline in Caucasians, Barnes said.