Source: New Perspectives on Medicine
Recently, a study published in The Lancet Regional Health-Western Pacific added new evidence for the association between blood glucose fluctuations (variability) and obesity and cancer in people with diabetes. The study, from the Chinese University of Hong Kong, showed that if diabetics have large blood sugar fluctuations or obesity, the risk of cancer, especially breast and liver cancer, and the risk of death are significantly increased.
Screenshot from The Lancet Regional Health Western Pacific
Overview of the study
According to the Global Diabetes Map released by the International Diabetes Federation (IDF) in 2021, there are 537 million adult diabetics aged 20 to 79 years old worldwide, while the number of adult diabetic patients in China has reached 141 million, with a prevalence of up to 13%. Previous studies have shown that diabetes is associated with cancer risk, and cancer is becoming the leading cause of death in people with diabetes. In addition to prostate cancer, diabetics have a 1.5 to 2-fold increased risk of developing systemic cancer. Obese patients with fluctuating blood sugar may reduce their risk of cancer by lowering their weight and blood sugar.
In this prospective cohort study, the researchers used a COX proportional risk model to assess the risk association of blood glucose fluctuations with cancer at all sites (the primary findings of the study) and death from cancer-specific causes (secondary outcomes of the study), and also explored the combined effects of obesity and blood glucose fluctuations.
Glycosylated hemoglobin (HbA1c) is one of the diagnostic and glycemic control criteria recommended by the World Health Organization (WHO). In the study, the degree of blood glucose fluctuations (blood glucose variability) was assessed by the HbA1c Variability Score (HVS), which was defined as the number of times the HbA1c value changed by 0.5% compared to the previous visit.
The study included 15,286 Chinese patients with a diabetes course ≥ 10 years, an observation time of ≥ 3 years, and at least 5 HbA1c measurements.
thereinto:
➤There were 15,054 cases of type 2 diabetes, accounting for 98.5%; 232 cases of type 1 diabetes;
➤51.7% of patients were male, mean age 61.04 years, mean HbA1c: 7.54%, mean body mass index (BMI): 25.65 kg/m²;
➤ There were 928 cases of cancer in all areas, of which 404 died of cancer.
Obesity, high blood sugar fluctuations, and a high risk of cancer
An analysis of the study found that:
➤ There is a nonlinear relationship between the specific HVS values and the cancer outcome, but after stratification by the HVS median (42.31), there is a linear relationship between the high HVS group and the low HVS group and the cancer outcome;
➤ In the high HVS group, for every standard deviation increased by HVS, the risk of cancer in all sites increased by 15%, the risk of breast, liver and colorectal cancer increased by 44%, 37%, and 9%, respectively, and the risk of cancer death, vascular death, and non-cancer non-vascular death increased by 21%, 27%, and 15%, respectively;
➤ If the body mass index ≥25kg/m² is used as the diagnostic criterion for obesity, further distinguish, compared with low HVS and non-obese patients, the risk of cancer, breast cancer and liver cancer in all parts of high HVS and obese patients increased by 42%, 1.44 times and 1.63 times, respectively, and the risk of cancer death, vascular death and non-cancer non-vascular death increased by 45%, 47% and 35%, respectively;
➤ In sensitivity analyses, these associations remained unchanged regardless of disease duration and number of HbA1c measurements.
Image source: Visual China
In summary, obesity and high blood glucose fluctuations are associated with an increased risk of cancer, breast cancer, liver cancer, and cancer-specific death in patients with diabetes. The paper notes that it is worth noting that about 1 in 4 of all diabetics are at high risk of both obesity and large blood glucose fluctuations.
The results suggest that optimizing blood glucose and weight control to reduce the risk of cancer development and cancer death is feasible, especially for patients with poor glycemic control and fluctuations. Therefore, the identification of these high-risk patients for intensive management will have an important impact on individual health.
Comprehensive control goals for type 2 diabetes
The "China Guidelines for the Prevention and Treatment of Type 2 Diabetes (2020 Edition)" pointed out that patients with T2DM often have one or more components of metabolic syndrome, such as hypertension, dyslipidemia, obesity, etc., which significantly increases the risk, progression rate and harm of T2DM complications.
Therefore, scientific and reasonable T2DM treatment strategies should be comprehensive, including blood glucose, blood pressure, lipids and body weight control, and antiplatelet therapy when indications are available. Control of blood glucose, blood pressure, blood lipids, and body weight should be based on lifestyle improvements and appropriate drug therapy depending on the patient's specific circumstances.
Glycemic control and weight management strategies
The control of blood glucose is of great significance in the metabolic management of diabetes. HbA1c is the most important indicator of glycemic control. HbA1c control targets should be developed in a balance between the benefits of large blood vessels and microvascular and the risk of adverse reactions (hypoglycemia, weight gain, etc.). The recommended control target for HbA1c in most nonpregnant adult patients with T2DM is <7%.
Through reasonable weight management, overweight and obese patients with T2DM can not only improve blood sugar control and reduce the use of hypoglycemic drugs, but also some diabetic patients can stop hypoglycemic drugs to achieve a state of "remission" of diabetes.
Weight management in patients with diabetes should also follow the principle of individualization, that is, comprehensive consideration according to the patient's age, disease course, life expectancy, severity of complications or comorbidities, etc. Weight management strategies in overweight and obese adultS with T2DM include lifestyle interventions, the use of hypoglycemic or diet pills with weight-loss effects, and metabolic surgery.
bibliography:
Diabetes Branch of Chinese Medical Association. Guidelines for the prevention and treatment of type 2 diabetes in China (2020 edition)[J]. Chinese Journal of Diabetes. 2021, 13 (4):317-411.
[2] DandanMao, Eric S.H. Lau, Baoqi Fan et al., (2021). Risk associations of long-termHbA1c variability and obesity on cancer events and cancer-specific death in15,286 patients with diabetes - A prospective cohort study. The Lancet RegionalHealth Western Pacific. DOI: https://doi.org/10.1016/j.lanwpc.2021.100315