S1W1 Obesity and Energy Balance part 4

Question 1

Discuss BMI’s association with mortality

Answer 1

• biggest data set available produced by Global BMI Mortality Collaboration (2016)
• a study where they pulled lots and lots of different prospective cohorts and looked at the risk of premature mortality according to BMI classfications
• as BMI increases from normal, risk of premature mortality increases
• also a very low BMI is associated with premature mortality
• obesity doesn’t just increase the risk of death, it increases the risk of having many metabolic conditions such as hypertension, type 2 diabetes
• risk of premature mortality becomes signifcant with a BMI of 30 and as it gets more severe so BMI of 35, the risk goes up massively

Question 2

Explain what multimorbidity is

Answer 2

• obesity is a huge risk factor for a lot of complex medical conditions
• tend to get a constellation of these conditions, obese patients often have a combination of metabolic conditions such as impaired lipids, type 2 diabetes, hypertension etc and become quite complicated patients
• having more than one of these metabolic conditions is called multimorbidity

Question 3

Explain what mechanical stress of obesity on the joints can lead to

Answer 3

The physical weight of carrying around all the excess adipose tissue can have really problematic effects such as arthritis.

Question 4

Briefly explain 4 ways in which the mechanical stress of obesity leads to problems

Answer 4

• increased intraabdominal pressure can cause various types of reflux disease such as gastroesophaggeal reflux disease
• increased mechanical load on joints leads to osteoarthritis
• increased pharyngeal soft tissue (fat stored around the face and neck) leads to sleep apnoea
• renal compression leads to systematic and pulmonary hypertension

Question 5

What is the purpose of adipose tissue and how does it cause problems?

Answer 5

• Adipose tissue is not just an inert storage depot for excess fat, it is a metabolic organ that produces hundreds of proteins, thousands of metabolites, these get into the circulation and affect other tissues such as skeletal muscle, liver, pancreas and so on
• Adipokines are basically proteins/hormones made by fat cells, as your fat cells become large and stressed, they release inflammatory proteins which cause insulin resistance and leads to diabetes
• Lots of adipose tissue, lots of adipocytes leads to more fatty acids circulating in the blood, these fatty acids are toxic and can lead to all sorts of problems
• If your lipids/cholesterol are not in balance, dyslipidaemia leads to coronary artery disease, stroke etc

Question 6

Briefly explain what chronic low grade inflammation is

Answer 6

• It is prompted by having too many fat cells which become enlarged and stressed, they attract immune cells, immune cells start spitting out cytokines, these are pro inflammatory and cause this state of chronic low grade inflammation
• this is linked to things like insulin resistance and damage to the vascular system and therefore cardiovascular disease