Lecture 3: Blood Pressure & Environment

Question 1

What is the primary source that explains variation between populations?

Answer 1

Environment

Question 2

What is the primary source that explains variation between individuals?

Answer 2

Genes

Question 3

What is the primary source that explains variation within individuals?

Answer 3

Environment

Question 4

What explains the high BP correlation between DZ twins?

Answer 4

Exposed to the same things in the environment at the same time

Question 5

What explains the low BP correlation between parent-offspring?

Answer 5

Generation (lifestyle) gap

Question 6

How can you determine specific environmental factors?

Answer 6

Hard to pin down & identify in individuals
More obvious between populations than within
Observational analyses
Interventional studies - test the hypothesis
Both won’t tell you causation

Question 7

Why shouldn’t we lower population sodium levels?

Answer 7

Causes harm
Babies need Na
During summer the elderly aren’t good at retaining Na

Question 8

What environmental factors can we use to manipulate BP?

Answer 8

Diet

BP

Question 9

What impact does a low salt or high potassium diet have on BP in hypertensive subjects?

Answer 9

Reduces BP

Question 10

What did the INTERSALT study find?

Answer 10

Weak correlation between populations - steeper in elderly

No correlation within populations

Question 11

How much salt is in a litre of ECF?

How much Na intake per day roughly?

Answer 11

150mmol/L

150mmol/day

Question 12

From what age does renal function begin to deteriorate?

How much do you lose per year?

Answer 12

Age 40
1ml/min/1.73m squared
GFR = 1.73m squared (average Sa of a 70kg person)

Question 13

How does increased alcohol intake impact BP?

Answer 13

Increases BP

independent of age, sex, obesity, smoking, coffee, education

Question 14

Can increased BP from drinking alcohol be reversed?

Answer 14

Yes

Seems to involve sympathetic nerves

Question 15

Can diuretics lower BP in the elderly?

Answer 15

Yes

Question 16

Can magnesium or calcium reduce high BP?

Answer 16

Controversial

Not widely accepted

Question 17

Is there a relationship between BP and dietary intake of total fats, saturated, monosaturated and polyunsaturated fats?

Answer 17

No

Question 18

Can wa-polyunsaturated fats lower BP in hypertensive subjects?

Answer 18

Yes

> 4grams/day

Question 19

Do vegetarians have a lower BP?

Answer 19

Yes, less fat?

Question 20

How does exercise impact BP?

Answer 20

Fitter = lower BP

Probably involves sympathetic nerves

Question 21

Can psychological stress impact BP?

Answer 21

Difficult to measure

No reliable conclusions

Question 22

Can smoking impact BP?

Answer 22

BP rises during smoking
BUT
Long term smokers have lower BP (lower BMI? Appetite suppression?)

Question 23

What type of studies are used to monitor variation in BP between populations?

Answer 23

Migration studies

Compare the lifestyle from where they came from to where they have moved

Question 24

What factors influence variations in populations?

Answer 24

Social
Economic
Psychological
Biological
Lifestyle