The risks of overweight and obesity
NICE defines a healthy adult BMI as 18.5 to 24.9.
Health risks associated with
increasing body mass index (BMI)
Coronary artery disease (CAD) and stroke
- 3.6 x risk of CAD for each unit change in BMI.
- Dyslipidaemia progressively develops as BMI increases from
21kg/m² with rise in small particle low-density lipoprotein.
- 70% of obese women with hypertension have left ventricular
hypertrophy.
- Obesity is a contributing factor to cardiac failure in > 10%
of patients.
- Overweight/obesity plus hypertension is associated with
increased risk of ischaemic stroke.
Hypertension
- 5x risk in obesity: 66% of hypertension is linked to excess
weight, and 85% of hypertension is associated with a BMI >
25kg/m2.
Type 2 diabetes
- 90% of type 2 diabetics have a BMI >
23kg/m2.
(Health risks associated with overweight
and obesity. Obesity Reviews [2007] 8 [Suppl.1], 13–17)
Obesity risks
The World Health Organisation considers
someone obese if they have a body mass index (BMI) of 30 or above.
It estimates that at least 300 million people are now obese.
Over 40 serious health conditions are linked
to obesity, including:
- High blood pressure, high cholesterol,
coronary heart disease, deep vein thrombosis, varicose veins.
- Type 2 diabetes, insulin resistance,
polycystic ovary syndrome, infertility, breast cancer.
- Breathlessness, obstructive sleep
apnoea.
- Gallstones, hiatus hernia, fatty liver, colon
cancer.
- Arthritis, back pain.
- Stress incontinence.
- Depression, low self-esteem, binge-eating
disorder.
(National Obesity Forum, 2008)
- Someone dies from an obesity-related illness
in England every 17 minutes (Tackling Obesity In England,
2001).
- At BMI 30-35, mean survival is reduced by two
to four years. At BMI 40-45, it is reduced by eight to ten years,
which is comparable with the effect of smoking (Lancet, early
online publication, 18 March 2009).
- Obese women are 13 times more likely to
develop type 2 diabetes than non-obese women. Obese men
are five times more likely to develop type 2 diabetes than
non-obese men (The Information Centre – NHS Statistics on
obesity, physical education and diet: England, 2006).
- Obesity will soon surpass smoking as the
biggest cause of premature loss of life (House of Commons,
2004).
The benefits of 10% weight loss
|
|
Mortality
|
> 20% reduction in total
mortality
> 30% reduction in diabetes-related
deaths
> 40% reduction in obesity related
cancers
|
|
Blood pressure
|
> 10 mmHg reduction in
systolic
> 20 mmHg reduction in diastolic
|
|
Diabetes
|
> 30-50% reduction in fasting
glucose
> 50% reduction in risk of
developing diabetes
> 15% reduction in HbA1c
|
|
Lipids
|
> 10% reduction in total
cholesterol
> 15% reduction
in LDL-cholesterol
> 30% reduction
in triglycerides
> 8% increase
in HDL-cholesterol
|
(Adapted from Jung R. Obesity as a disease. Br Med Bull
1997;53(2):307–321; in National Obesity Forum)