Are we overestimating the beneficial effects of moderate alcohol consumption in later life? The sick...
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Transcript of Are we overestimating the beneficial effects of moderate alcohol consumption in later life? The sick...
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
2Corrao, G, et al, Addiction, 2000. 95(10): p. 1505-1523.
Alcohol consumption against risk of coronary heart disease
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
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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)
Implications of the J-shape
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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
Odd
s R
atio
(an
d 95
% C
.I)
8
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.
Odds of being a non-drinker vs. drinker aged 18 to 34 yearsHealth survey for England 2006 & 08
Highest QualificationIncome
Odd
s R
atio
(an
d 95
% C
.I)
9
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.
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?
HypothesesA. Poor health precedes non-drinking early in the life course
B. Continuous poor health is associated with continuous non-drinking
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Data sets
The National Child Development Study 1958 (NCDS)
The British Cohort Study 1970 (BCS)
A
AB
B
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Data sets
The National Child Development Study 1958 (NCDS)
The British Cohort Study 1970 (BCS)
A
AB
B
12
BCS 1970Self-report conditions suffered since 16 years
reported at 26 years (p<0.05)
Drinking frequency at 26 years14
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
Adjusted for sex, highest qualification, marital status, parental status and malaise score
Lifetime abstainers
33 yearsNo
LLSI LLSI23 yearsNo LLSILLSI
Life time abstainers
Self-identified LA
30 years 30 yearsNo LLI LLI
NO LLI LLI
26 yearsNo LLI 1 0.80 1 1.29LLI 1.14 2.80*** 2.07* 2.11*
NCDS 1958 BCS 1970
1 1.442.82** 4.50**
NG FAT, L., et al (2013) Journal of Epidemiology and Community Health, doi:10.1136/jech-2013-202576
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Odds ratios
Adjusted for sex, highest qualification, marital status, parental status and malaise score
Lifetime abstainers
42 yearsNo
LLSI LLSI23 & 33 yearsNo LLSI 1 2.13**LLSI 3.16*** 7.02***
Life time abstainers Self-Identified LA
34 years 34 years
No LLI LLINO LLI LLI
26 &30 yearsNo LLI 1 1.02 1 1.13
LLI 1.71 3.33*** 2.02** 2.80***
NCDS 1958 BCS 1970
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NG FAT, L., et al (2013) Journal of Epidemiology and Community Health, doi:10.1136/jech-2013-202576
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
Limitations•Small sample size of lifetime abstainers•Missing lost to attrition (MNAR)•Participants may drink in between waves
• 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)
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Acknowledgements: Dr Nicola Shelton, Dr Noriko Cable, Dr James Kneale, Professor Sir Michael Marmot
[email protected], @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.
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Impact