{'fraction_non_alphanumeric': 0.02702702702702703, 'fraction_numerical': 0.008765522279035792, 'mean_word_length': 4.9825327510917035, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Leptin declines in two phases during weight loss: Longitudinal analysis in children

Aim: To investigate leptin levels during weight loss in children in relation to indices of weight, puberty, energy balance (EB), insulin and soluble leptin receptor levels. Methods: One hundred and twenty children were followed longitudinally with nine consecutive assessments during a 3-mo programme consisting of low-fat diets and an abundance of physical activity. Results: During the study period, median body weight percent was reduced by 19.6% and median s-leptin levels by 17 ng/ml. Large declines in leptin levels to 38% of expected levels in boys and 53% in girls were beyond what could be expected when adjusting for weight percent, puberty, EB and insulin. The leptin decline was significantly different before and after 10 d of weight loss. Discussion: Leptin has previously been found to correlate with fat mass, puberty and EB. However, a large variation in leptin levels for a certain degree of fat mass has been described. A hypothetical contribution to leptin variability is that of altered leptin sensitivity and/ or set point levels. From this perspective, it is possible that the decline in leptin levels is an outcome of altered leptin sensitivity. Conclusion: The two-phase leptin decline suggests involvement of hitherto unknown regulators of leptin signalling.