Body Mass Index (BMI)

Transcription

1 Body Mass Index (BMI) CITY GATE TRAINING CENTRE ALL RIGHTS RESERVED

2 The Body Mass Index (BMI) BMI is a heuristic (experience based) technique in determining healthy body weight considering average body composition using only weight and height as variables. You do not actually measure the percentage adiposity (fat). So if you require to determine BMI, you need to take the height of the person and their weight.

3 Collecting Data For BMI Calculation Weight First of all, introduce yourself to the service user explaining the procedure, why you need to carry it out and wash your hands. Remember good communication skills. If person is wearing heavy clothing + shoes, you may ask them to remove it. But please note you need to reflect on cultural differences. Explain why it is important. You may need to take 1-2kg due remaining clothing. Ask person to step on digital clinical scales, wait for the reading to stabilise (i.e. no changes in numbers occur) and record the measurement. Inform person of the results, especially important if person has poor vision/ blind.

4 Collecting Data For BMI Calculation Height Nicely ask patient to remove their shoes. You need to record height accurately. Nicely ask person to step next to stadiometer and stand up straight with their back in parallel to the meter. Ask person to be still for a moment and regulating the movable arm place it gently on their head. Remember good commination skills so that patient actively take part in the procedure. Thank patient and inform of the results. Clearly record the reading. This is important as it will be used for calculation or used for charts. Well recorded data will be easily readable by you and colleagues.

5 Adult BMI Chart Adults in BMI charts are individuals 21+ years and the chart is below. Underweight: 18.5 kg/m² Normal: 18.5 to 25 kg/m² Overweight: 25 to 30 kg/m² Obese: 30+ kg/m² Morbidly obese: 40+ kg/m²

6 Children BMI Chart o Children in BMI charts are individuals up to and including 20 years. BMI is used differently for children and it is split in GIRLS and BOYS charts due to different growth rates at a different age. For instance GIRLS grow faster at the start, while BOYS grow faster later. o BMI for children is calculated exactly the same way as for adults, but then compared to typical values for other children of the same age. Instead of set thresholds for underweight and overweight, then, the BMI percentile allows comparison with children of the same sex and age.

7 Children BMI Chart Explained BMI that is less than the 5 th percentile is considered underweight and above the 95 th percentile is considered obese for people 20 years of age and younger. BMI between the 85 th and 95 th percentile are considered to be overweight, while 5 th to 85 th percentile it is considered normal weight.

8 How To Calculate BMI

9 Practical Question 1

10 Practical Question 2

11 Practical Questions 3 and 4:

12 NHS BMI Chart and How to Use It Questions: 1. A gentleman 25 years old, height 1.75m and weight 70.3kg. 2. A lady 44 years old, height 1.68m and weight 81.6kg. 3. A lady 23 years old, height 1.80m and weight 65.8kg. 4. A gentleman 22 years old, height 1.79m and weight 66.0kg. Answers: 1. 21, normal , overweight borderline clinically obese , underweight or 18 both are acceptable, underweight either way, look for closest values. W eig ht in kil og ra ms (kg ) Height in metres (m)

13 Health Risks Associated with Very Low BMI (Underweight BMI Below 18.5kg/m²) Anaemia plus Weaker Immune System Less Energetic and Poor Temperature Control (More Susceptible to Hypothermia). Osteoporosis, Weaker Bones plus Weaker Muscle Strength Wounds Take Longer to Heal Infertility in Females plus Irregular Menstruation Cycles Miscarriages Risk Increase

14 Health Risks Associated with Very High BMI (Obese BMI Higher than 30kg/m²) Heart Problems including High Blood Pressure (Hypertension) and Fast Heart Rate (Tachycardia) Heart Attack and Stroke Risk Increased Feeling Weak and Tired plus Sleep Apnoea (Poor Sleep Quality) & Difficulties with Breathing (Especially During Exercise and Labour) Poor Mobility/ Mobility Problems for Instance extra Strain Metabolic Disorders such as Type 2 Diabetes plus Increased Risk to Suffer From Cancer i.e. Colon, Breast and Endometrium (Womb) Cancers Gallstones, Fatty Liver, Higher risk High Cholesterol

15 Obesity (BMI >30) and Pregnancy High BMI can result in fertility problems and irregular/ stopped menstrual cycles, therefore sometimes weight loss may be encouraged, but NO WEIGHT LOSS during pregnancy. More than 50% of maternal death in the UK are associated with obesity (CEMACH, 2007). Obesity is also linked with adverse effects during pregnancy and labour (CEMACH, 2007). Increased risk of Gestational Diabetes Mellitus, diabetes during pregnancy. Increased risk of pre-eclampsia, revise other course topics for more information. Increased risk of genital and urinary tract infections due to fat-folds that harbour bacteria. Intrauterine infant death, stillbirth. Macrosomia, new-born with excessive weight, and metabolic disorders. Congenital anomalies, birth defects.

16 Obesity (BMI >30) and Pregnancy Continued Increased chances of Postpartum haemorrhage, bleeding after delivery plus further complications. Due to low mobility and excessive adiposity, increased risk of blood clot formation. Increased risk of gestational hypotension and hypotension abnormalities. Increased rates of Caesarean Section (CS) and infections after. Increased risks of premature delivery, premature birth higher risk for baby to die. Increased risk of spontaneous abortion. Problems with ultrasound screening resulting in chances of missing potential development problems and disorders.

17 BMI Issues Recently BMI is becoming a debatable subject and more and more research states that BMI is not very accurately determining risks of metabolic disorders such as type 2 diabetes and heart problems. Furthermore, those with lean bodies (i.e. body builders/ athletes) can high BMI, while those with excess adiposity (fat) can have BMI that in reality does not show the risk factors associated (i.e. BMI of 29.8 overweight, but person has a lot of belly fat meaning high risk). New factor has been introduced, Circumference of Abdominal area just below the ribs. This is introduced next to BMI to more accurately reflect on risks. So you might be asked to do that in GP or Hospital you might work in.

18 Multiple Choice Question 1: --- Correct Answer (D)

19 Multiple Choice Question 2: You are working in GP Surgery. One of your patients is 30 years old male, height 1.92 and weight 90kg. You calculated his BMI and it is His BMI is: A) Normal. B) Obese. C) Normal, borderline underweight. D) Overweight. --- Correct Answer (A)

20 Multiple Choice Question 3: You are working in a hospital surgery and you have a 23 years old female. You need to calculate her BMI. Her height is 1.84m and weight is 55kg. Using the BMI table, determine her BMI: A) 22 B) 32 C) Correct Answer (C) D) 18

21 Any Questions?

22 References: BBC (2006) Calculate your body mass index. Available at: Accessed on: 15 th January Food standards agency (2010) BMI calculator. Available at: tor/. Accessed on:16 th January Overweight and Obesity in Pregnancy: A Review of Evidence, Jennifer R. Bernier and Yvonne Hanson (2012). Available at: Accessed on: 16 th January Weight Expectations: Experiences and Needs of Overweight and Obese Pregnant Women and their Health Care Providers, Jennifer Bernier (2013). Available at: Womens-Health/projects-and-publications/obesity/pregnancy-and-obesity.html. Last accessed 16 th January NHS Choices (2012) Why My Waist Size Important. Available at: Accessed 21 st January 2014.