Cortisol secretion pattern in overweight/obese and normal-weight infants: a cross-sectional study

Area of Science:

• Endocrinology
• Pediatric Health
• Circadian Biology

Background:

• Salivary circadian cortisol is crucial for infant growth and development.
• Abnormal cortisol levels may increase the risk of developing obesity later in life.
• The cortisol secretion pattern in overweight/obese infants compared to normal-weight infants is not well understood.

Purpose of the Study:

• To investigate and compare the salivary cortisol secretion patterns between overweight/obese infants and normal-weight infants.
• To identify potential differences in diurnal cortisol rhythm related to infant weight status.

Main Methods:

• Saliva samples were collected from 33 infants (6-24 months old) at four time points: upon awakening, 30 min after waking, midday, and before bedtime.
• Participants were categorized into overweight/obese (n=17) and normal-weight (n=16) groups.
• Cortisol levels were analyzed using highly sensitive enzyme immunoassays.

Main Results:

• No significant differences in overall salivary cortisol levels were found between the overweight/obese and normal-weight infant groups at any of the four time points or in the area under the curve (AUC).
• The overweight/obese group exhibited a significant reduction in cortisol from morning (T1, T2) to bedtime (T4).
• The normal-weight group showed a reduction in cortisol from morning (T1) to midday (T3) and a further decrease by bedtime (T4).

Conclusions:

• Infants who are overweight or obese display a distinct diurnal salivary cortisol secretion pattern compared to normal-weight infants.
• Despite differing patterns, absolute cortisol levels did not differ between the groups, suggesting subtle alterations in rhythm rather than concentration.
• These findings may offer insights into early endocrine markers associated with weight status in infancy.