Body mass index (BMI) is used to measure body fat. BMI uses your height and weight to work out if your weight is healthy. The BMI calculation divides an adult's weight in kilograms by their height in metres multiplied by itself (weight / (height x height)).
According to the NHS, an adult with a BMI of 30 or above is obese. This is based on the increased chance of death for adults from White ethnic groups at a BMI of 30 or above. Adults from minority ethnic groups including those from black, South Asian, Chinese, and Arab ethnic groups may experience increased risk of health problems or death at lower BMIs than white ethnic groups.
We do not have the correct BMI values for obesity for people from minority ethnic groups. Our research will produce new BMI values for obesity to assess risk for diabetes, heart attack, stroke, cancer (bowel cancer, breast cancer), and death, separately, among Black (Caribbean, African), South Asian (Indian, Pakistani, Bangladeshi), Chinese, Arab, and mixed ethnic groups.
To do this, we will analyse patient data routinely recorded by peoples general practitioner linked to hospital records in England. We will determine BMI values among adults from minority ethnic groups that match a BMI of 30 in white populations in relation to developing diabetes, a heart attack, stroke, cancer or death. Our findings can help healthcare professionals make better decisions on when to assess for health problems related to obesity or start lifestyle changes.
Aim: We aim to prospectively identify obesity BMI cut-off points for the risk of type 2 diabetes, myocardial infarction, ischaemic stroke, colorectal cancer, postmenopausal breast cancer and all-cause mortality, among adults from minority ethnic groups that are risk equivalent to the current obesity BMI cut-off point set for white populations.
Background: The National Institute for Health and Care Excellence (NICE) and World Health Organization (WHO) definition of obesity, e.g. body mass index (BMI) ? 30 kg/m2 may underestimate risk of chronic disease in non-white adults. Ethnic minority populations have a higher risk of type 2 diabetes at lower obesity BMI cut-off points than white populations. NICE does not consider the evidence sufficiently strong to make recommendations on the use of new BMI cut-off points to classify individual minority ethnics groups as obese.
Methods: We will assemble a cohort of adults, aged ?18 years and free from diagnosed type 2 diabetes, myocardial infarction, ischaemic stroke, colorectal cancer, postmenopausal breast cancer at baseline from white, black, South Asian, Chinese, Arab, and mixed ethnic groups using linked electronic health records covering primary care, hospital admissions, acute coronary syndrome registry and mortality registry (CALIBER platform). Ethnic specific obesity BMI cut-off points related to risk of incident type 2 diabetes, incident myocardial infarction, incident ischaemic stroke, incident colorectal cancer, incident postmenopausal breast cancer and all-cause mortality, respectively will be estimated using Poisson regression, adjusting for age and sex. Analyses will be repeated with additional adjustment for smoking status, and patient-level Index of Multiple Deprivation (IMD) score.
Anticipated impact and dissemination: Anticipated impact among minority ethnic groups includes: (a) increased identification of obesity to trigger culturally-appropriate action to prevent obesity-related chronic conditions; (b) greater awareness of increased risk of chronic disease at lower BMI cut-off points compared with those from white populations; (c) informing NICE Guidelines
Type 2 diabetes, myocardial infarction, ischaemic stroke, colorectal cancer, postmenopausal (>55 years) breast cancer, endometrial cancer, death, or transfer out of the practice.
Rishi Caleyachetty - Chief Investigator - University of Warwick
Rishi Caleyachetty - Corresponding Applicant - University of Warwick
Amitava Banerjee - Collaborator - University College London ( UCL )
Francesco Cappuccio - Collaborator - University of Warwick
Kenan Direk - Collaborator - University College London ( UCL )
Nuredin Ibrahim Mohammed - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Paramjit Gill - Collaborator - University of Warwick
Rebecca Hardy - Collaborator - University College London ( UCL )
Ricardo Uauy - Collaborator - University of Chile
Rohini Mathur - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Thomas Barber - Collaborator - University of Warwick
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation