Adipose cellularity as a measurement of long-term changes in body weight: a Swedish cohort study spanning 1988-2016.

Background: Adipocyte size and number (cellularity) determine the adipose mass and may relate to long-term body weight changes.

Methods: We investigated 1014 healthy participants at Karolinska Institutet in Sweden 1988-2016 for body weight and size/number of subcutaneous adipocytes, and 273 for visceral adipocyte size. We measured body weight on 281 subjects about 16 years later. We analysed the association of baseline adipocyte size and number with body weight changes by linear regression including relevant co-factors, and the associations of cellularity (low or high number of either large or small adipocytes) regarding body weight changes by analysis of variance.

Findings: Subcutaneous adipocyte size and number and visceral adipocyte size showed strong relationships with body weight changes irrespective of its mode of expression (adjusted r ≥0·15). The relationships were significant (p ≤ 0·027) independent of co-factors (age, sex, initial body weight or height, body fat, obesity, nicotine use, physical activity, and observation time). Interventions (lifestyle change or bariatric surgery) did not influence the associations (p = 0·86). A low or high number of large adipocytes associated with body weight loss, whereas a low or high number of small cells associated with weight stability or weight gain.

Interpretation: Adipose cellularity is associated with long-term changes in body weight, following interventions to decrease body weight. Patients with a high number of large fat cells experienced the most pronounced weight reduction.

Funding: The Stockholm County Council (963296, 994175, 986118), the Center for Innovative Medicine at Karolinska Institutet (986109) and the Swedish Society of Medicine (1001156). None of the funding sources had any involvement in the study.