Effects of weight loss and weight gain on HbA, systolic blood pressure and total cholesterol in three subgroups defined by blood glucose: a pooled analysis of two behavioural weight management trials in England.
BMJ Open 2025 ; 15: e095046.
Pidd K, Breeze P, Ahern A, Griffin SJ, Brennan A
DOI : 10.1136/bmjopen-2024-095046
PubMed ID : 40233948
PMCID : PMC12004498
URL : https://bmjopen.bmj.com/content/15/4/e095046
Abstract
To estimate the association between weight and cardiometabolic risk factors across subgroups of individuals with normoglycaemia, non-diabetic hyperglycaemia and type 2 diabetes (T2D) and to explore whether the association differs between weight loss and weight gain.
Observational analysis using mixed-effects regression models of pooled trial data.
The Weight loss Referral for Adults in Primary care (n=1267) and Glucose Lowering through Weight management (n=577) trials recruited individuals with overweight or obesity (body mass index, BMI >25 kg/m) from primary care practices across England.
The primary outcome measures were the relationships between a change in (BMI; kg/m) and a change in glycated haemoglobin (HbA; mmol/mol), total cholesterol (mmol/L) or systolic blood pressure (SBP; mm Hg) across three subgroups of individuals with: normoglycaemia, non-diabetic hyperglycaemia and T2D. Secondary outcomes included the influence of weight loss versus weight gain on these relationships.
HbA is positively related to a change in BMI, and a 1 kg/m change was related to a 1.5 mmol/mol (95% CI: 1.1 to 1.9) change in HbA in individuals with T2D, 0.6 mmol/mol (95% CI: 0.4 to 0.8) change in those with non-diabetic hyperglycaemia and 0.3 mmol/mol (95% CI: 0.2 to 0.4) change in those with normoglycaemia. In individuals with normoglycaemia, weight gain has a larger impact on HbA than weight loss, with a 0.5 mmol/mol (95% CI: 0.3 to 0.7) increase per 1 kg/m2 gained, compared with a relationship that is 0.3 mmol/mol smaller (95% CI: -0.6 to -0.1) per 1 kg/m of weight loss. BMI reduction improved SBP and total cholesterol significantly; however, effects did not differ between the three subgroups.
Cardiometabolic risk factors are associated with changes in weight. The association with HbA varies by diabetes status, with increasing magnitude in those with non-diabetic hyperglycaemia and T2D. Weight gain has a larger impact on HbA than weight loss in individuals with normoglycaemia, implying an asymmetric relationship.