Stress in Seniors Linked to Low Birth Weight

Low birth weight children may be at a greater risk of stress-related health problems as adults, according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM).

Findings from this study show that low birth weight (below the 10th percentile) can lead later in life to low concentrations of cortisol, a hormone that regulates stress response by adjusting blood pressure and blood sugar levels. An imbalance in cortisol can result in a host of common adult diseases, such as coronary heart disease and diabetes. This study indicates that there may be a link between fetal life conditions and adult disease.

"The study showed that people who were born with low birth weight, now between the ages of 60 to 70, have a much lower cortisol response to stress than those with average birth weights,” said Ero Kajantie, M.D., Ph. D., a senior researcher at the National Public Health Institute in Helsinki, Finland, and lead author of the study. “People with low birth weight may be more vulnerable to long-lasting effects of psychosocial stress, which may lead to low cortisol stress response."

In this study, 287 men and women born between 1934 and 1944 underwent a standardized psychosocial stressor (a stress test) in conjunction with having their cortisol and adrenocorticotropic hormone (ACTH) concentrations measured. Researchers found the lowest cortisol and ACTH concentrations were seen in subjects with the lowest birth weights.

Studies in humans and animals have suggested fetal life conditions and adult disease are linked through the intrauterine programming of the hypothalamic-pituitary-adrenal axis (HPAA). HPAA refers to the complex set of interactions between the hypothalamus, pituitary gland, and adrenal gland. This set of interactions controls stress response, and regulates various body processes, including digestion, the immune system, mood and sexuality, and energy usage.

Researchers have established a link between low birth weight and decreased HPAA activity in adult life, which itself is linked to a number of disorders such as post-traumatic stress disorder, fibromyalgia, and chronic fatigue syndrome.

“This finding may help to explain why people with low birth weight have an increased risk of certain common diseases such as coronary heart disease, type 2 diabetes and depression,” said Kajantie. “Identifying the mechanisms of this link will help to find ways to prevent these diseases early in life."

Other researchers working on the study include Kimmo Feldt, Katri Raikkonen, David I.W. Phillips, Clive Osmond, Kati Heinonen, Anu-Katriina Pesonen, Sture Andersson, David J.P. Barker, and Johan G. Eriksson.

A rapid release version of this paper has been published on-line and will appear in the November 2007 issue of the Journal of Clinical Endocrinology & Metabolism, a publication of The Endocrine Society.