Are we overestimating the beneficial effects of
moderate alcohol consumption in later life? The
sick quitter and sick non-starter hypotheses
Linda Ng Fat
PhD Student
UCL Population Health
Supervisors: Dr Nicola Shelton, Dr Noriko Cable, James
Kneale, Professor Sir Michael Marmot
The J/U-Curve among middle age cohorts in
observational studies
Alcohol consumption against risk of coronary heart disease
Corrao, G, et al, Addiction, 2000. 95(10): p. 1505-1523.
2
J-Curve for Total mortality; ex-drinkers separated
Klatsky, A. L. and N. Udaltsova (2007). Annals of Epidemiology 17(5): S63-S67
3
Is the relationship causal?
• Meets Bradford Hill Criteria of Consistency of findings and biological
plausibility
- Alcohol may increase high-density lipoprotein (HDL) cholesterol
• Some evidence to suggest this is the case from RCT & change in
biomarkers. But limited due to
– Small sample size & duration
– No RCT for incidence of CVD
Thus majority of studies have relied on observational data
4
Examples of reporting in the media
Source: BBC News
5
Implications of the J-shape
A health message that is confusing?
• 26% of people drink alcohol because they believe
it to have health benefits (Mintel 2004).
• In US a third cited possible health benefits as a
motivation, whilst only 10% identified breast
cancer as a risk (Mukamal et al 2008)
6
Further criticisms outside the sick-quitter
bias
1. Moderate drinkers have a better social position
and adopt healthier lifestyles than non-drinkers.
2. Validity of the ‘lifetime abstainer group’
3. Poor health may be a reason why some people
never ever start drinking
7
Odds of being a non-drinker vs. drinker aged 18 to 34 years
Health survey for England 2006 & 08
Odds Ratio (and 95% C.I)
4
2
1
0.5
0.25
Limiting
longstanding
illness
Anxiety or
depression
Anxiety or
depression
(missing)
Current
Smoker
High
Medium
Low
Overall Physical Activity
Adjusted for age, ethnicity, region, income, education, marital status, parental status, LLSI, anxiety, physical activity and smoking
NG FAT, L., & SHELTON, N. Addiction, 2012. 107(9): p. 1612-1620.
8
Odds of being a non-drinker vs. drinker aged 18 to 34 years
Health survey for England 2006 & 08
Odds Ratio (and 95% C.I)
4
2
1
0.5
0.25
Income
Highest Qualification
Adjusted for age, ethnicity, region, income, education, marital status, parental status, LLSI, anxiety, physical activity and smoking
NG FAT, L., & SHELTON, N. Addiction, 2012. 107(9): p. 1612-1620.
9
The Sick Non-starter hypothesis
• Non-drinkers have higher rates of self-reported poor health
in young adulthood (Power, C 1998) even after adjusting
for a range of social and demographic factors (Ng Fat, L &
Shelton, N 2012)
• Poor health a reason why some never ever take up
drinking?
Hypotheses
A. Poor health precedes non-drinking early in the life course
B. Continuous poor health is associated with continuous nondrinking
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Data sets
The National Child Development Study 1958 (NCDS)
A
Medical data
16 years
Non-drinker
23 years
The British Cohort Study 1970 (BCS)
Non-drinker
33 years
Non-drinker
42 years
B
A
Medical data
11 years
Non-drinker
26 years
Non-drinker
30 years
Non-drinker
34 years
B
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Data sets
The National Child Development Study 1958 (NCDS)
A
Medical data
16 years
Non-drinker
23 years
The British Cohort Study 1970 (BCS)
Non-drinker
33 years
Non-drinker
42 years
B
A
Medical data
11 years
Non-drinker
26 years
Non-drinker
30 years
Non-drinker
34 years
B
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NCDS 1958
Medical conditions at 16 years (p<0.05)
Heart & Haematological
Emotional or behavioural
Epilepsy, diabetes, any other
Physical disability
Eye, Speech, Hearing
At least one slight to severe disability
At least one condition
0
Never nowadays
5
Special Occasion
10
15
Less often
20
25
30
35
One to two times
40
45
50
Most days
Drinking frequency at 23 years
13
BCS 1970
Self-report conditions suffered since 16 years
reported at 26 years (p<0.05)
Fits, convulsions, epilepsy
Persistent trouble with teeth, gums or
mouth
Other health problem
Frequent problems with periods or other
gynaecological problems
Depression
Persistent joint or back pain
Wheezing when you have cold/flu
Migraine
never drink
0
5
10
special occasion
once/ twice a week
3/4 times a week
15 20 25
less often
30
35
40
most days
Drinking frequency at 26 years
14
Logistic Regression
Outcome:
1.Lifetime abstainer: Non-drinker in each sweep (NCDS 1958 and BCS
1970)
2.Self-identified lifetime abstainers: Current status measure from those
who reported “never having had an alcoholic drink” (BCS 1970)
Exposure:
Change in limiting longstanding illness since 23 (NCDS 1958)
Change in longstanding illness since 26 (BCS 1970)
Controls: Sex, malaise inventory score (mental health), highest
qualification, marital status, parental status
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Odds ratios
BCS 1970
NCDS 1958
Lifetime
abstainers
33 years
No
LLSI
LLSI
23 years
1.44
No LLSI 1
2.82** 4.50**
LLSI
26 years
No LLI
LLI
Life time
abstainers
Self-identified
LA
30 years
No
LLI
LLI
30 years
NO
LLI LLI
1
1.14
0.80
1
1.29
2.80*** 2.07* 2.11*
Adjusted for sex, highest qualification, marital status, parental status and malaise score
NG FAT, L., et al (2013) Journal of Epidemiology and Community Health, doi:10.1136/jech-2013-202576
16
Odds ratios
BCS 1970
NCDS 1958
Lifetime
abstainers
Life time
abstainers
42 years
No
LLSI
LLSI
34 years
23 & 33
years
No LLSI 1
2.13**
LLSI
3.16*** 7.02***
No LLI
26 &30
years
No LLI
LLI
1
1.71
LLI
Self-Identified LA
34 years
NO
LLI
LLI
1.02
1
1.13
3.33*** 2.02** 2.80***
Adjusted for sex, highest qualification, marital status, parental status and malaise score
NG FAT, L., et al (2013) Journal of Epidemiology and Community Health, doi:10.1136/jech-2013-202576
17
Conclusions and Implications
• Poor health from an early age and persistent poor
health is associated with persistent non-drinking
(lifetime abstention) from early adulthood
• Non-drinkers in later life may suffer from double
bias from sick-quitters and sick non-starters,
therefore may be an inadequate reference group
against drinkers
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Strengths
• Consistent findings from two large representative
cohorts and between two measures of non-drinkers
(lifetime abstainer and self-identified LA)
• Consistent findings between two measures of health
(LLI and LLSI)
Limitations
•Small sample size of lifetime abstainers
•Missing lost to attrition (MNAR)
•Participants may drink in between waves
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Acknowledgements: Dr Nicola Shelton, Dr Noriko Cable, Dr
James Kneale, Professor Sir Michael Marmot
l.ngfat.10@ucl.ac.uk, @linsng
NG FAT, L., CABLE, N., MARMOT, M. & SHELTON, N. (2013) Persistent long-standing illness
and non-drinking over time, implications for the use of lifetime abstainers as a control group,
Journal of Epidemiology and Community Health, doi:10.1136/jech-2013-202576
NG FAT, L., & SHELTON, N Associations between self-reported illness and non-drinking in
young adults. Addiction, 2012. 107(9): p. 1612-1620.
Impact
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