Practice Questions 4 Flashcards

1
Q

What is lifetime prevalence?

A

Proportion of individuals in population who have ever manifested a disorder who are alive on a given day.

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2
Q

What is lifetime morbid risk?

A

Probability of a person developing a disorder using entire period their life

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3
Q

Which lifetime calculation includes those deceased?

A

Lifetime morbid risk

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4
Q

For which type of disorders does age-specific incidence rates give approximate lifetime morbird risk?

A

Low incidence disorders

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5
Q

Calculation for attack rate

A

Number of cases that develop/number exposed in a cohort (at risk)

i.e. incidence rate following acute exposure

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6
Q

Who created the filter model/pathways of care

A

Goldberg

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7
Q

What is the infant mortality rate?

A

Deaths under 1 year of age

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8
Q

What type of bias does blinding reduce?

A

Measurement

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9
Q

What is a factorial RCT?

A

When 2 or more interventions are compared separetly but also in combination and against a control

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10
Q

How are screening tools usually evaluated?

A

Cross-section studies

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11
Q

Describe Guttman scalogram

A

If you agree to one statement you agree to all statements beneath it. Also known as cumulative scaling.

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12
Q

What is Guttmann scalogram useful for?

A

Hierarchical constructs e.g. political views

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13
Q

Describe positive skew

A

mean>median>mode

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14
Q

unit of coefficient of variation

A

%

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15
Q

Define coefficient of variation

A

the sample standard deviation divided by the sample mean of the data set

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16
Q

Where are the mean and mode in skewed distributions?

A

Mode are always on the shorter side

Mean are always on the longer side

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17
Q

Calculation for probability of one of two events occurring which are mutually exclusive

A

the sum of their probabilities, minus the probability that both will occur

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18
Q

What is multistage sampling?

A

2x sampling events.
Initially, the larger primary units are randomly selected (e.g. municipalities in a country). Later individual units (households) within primary units are randomly selected for measurement

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19
Q

What is disproportionate stratified random sampling?

A

If a subgroup of interest is extremely small, we may also use different sampling fractions (f) within the different strata to randomly over-sample the small group.
Within each stratum, all individuals have an equal chance of being selected for the study.

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20
Q

What is the target population?

A

The group to which we wish to generalize the results of a study.

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21
Q

What type of error can be caused by repeating test on the same set of data?

A

Type 1

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22
Q

Value of no difference for NNT?

A

Infinity

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23
Q

What is a necessary condition for Validity?

A

Reliability

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24
Q

Values of Cronbach’s alpha

A

-infinity to +1

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25
Q

What does Cronbach’s alpha measure?

A

Internal consistency

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26
Q

When is multiple regression used?

A

when we have one dependent (Y) variable and many independent (X) variables.

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27
Q

Purpose of multiple regression?

A

to find an equation that best predicts the Y variable as a linear function of the X variables.

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28
Q

What type of test is multiple regression?

A

Multivariate

Requires parametric data

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29
Q

What is a prerequisite for regression?

A

Correlation

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30
Q

What value of kappa implies perfect disagreement?

A

-1

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31
Q

What is kappa a measurement of?

A

Agreement

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32
Q

Degrees of freedom for chi square?

A

(number of rows-1) X (number of columns-1)

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33
Q

What does multivariate mean?

A

Multiple independent variables

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34
Q

IV and DV in logistic regression?

A

DV: categorical
IV: categorical, continuous or discrete

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35
Q

What tests can be used for paired data?

A

Wilcoxon rank sum
Sign
Paired t test

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36
Q

What is Wilcoxin used for?

A

Non-normal data from large samples

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37
Q

What does degrees of freedom mean?

A

The extent to which a set of observations are ‘free’ to vary

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38
Q

What test is used to compare two survival curves?

A

Log rank test

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39
Q

What does Cochrans criteria refer to?

A

Criteria that must be fulfilled if the chi-square test is to be used for testing statistical significance

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40
Q

What are Cochrans criteria?

A
  1. All expected values in each cell have a frequency count = 1 i.e. non-zero values
    2 At least 80% of total cells must have expected value of = 5
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41
Q

For which data type ca we use weighted kappa?

A

Ordinal

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42
Q

Assumptions for using ANOVA?

A
  1. Parametric distribution
  2. Equal variance amongst tested groups
  3. Independent observations
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43
Q

IV and DV for ANOVA

A

IV: categorical
DV: continuous

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44
Q

IV and DV for one-way ANOVA

A

IV: categorical
DV: continuous

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45
Q

What must be normally distributed for regression to be used?

A

DV

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46
Q

Calculation for Kappa

A

Kappa = Observed agreement beyond chance / Potential agreement beyond chance

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47
Q

What is the coefficient of determination (R^2)?

A

the proportion of the total variation in the dependent variable that is accounted for by the regression model (independent variable)

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48
Q

What does R^2 close to 1 imply?

A

that most of the variability in the dependent variable is explained by the regression model built using the predictors.

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49
Q

What is repeated measures ANOVA used for?

A

to compare paired observations within subjects across multiple groups.

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50
Q

What is the chi square equivalent for non-parametric data?

A

McNemars

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51
Q

What is the chi square equivalent for paired data?

A

McNemars

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52
Q

What is the type of sampling where every nth member is picked?

A

Systematic (non-random)

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53
Q

What is the name of the graph that is used to identify potential heterogeneity in which effect size is plotted against a measure of precision??

A

Galbraith plot

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54
Q

Level of non-significant difference for mean?

A

0

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55
Q

What is the normally accepted type 1 error rate?

A

5% (0.05 aka p value)

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56
Q

What is the square root of the variance?

A

SD

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57
Q

Which parametric test is used to compare 3 or more groups?

A

One-way ANOVA

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58
Q

IV and DV of logistic regression

A

DV: binary
IV: one or more

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59
Q

IV and DV for multiple linear regression?

A

1 DV

2 or more IV

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60
Q

What does multiple linear regression suggest?

A

Several IV together predict single DV

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61
Q

What is logistic regression used to predict?

A

Relationships between binary DV and several IV

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62
Q

When is logistic regression used?

A

If DV is binary

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63
Q

Calculation for population attributable risk

A

It is calculated by multiplying the attributable risk by the prevalence of exposure to the risk factor, and can be expressed by the formula PAR = Attributable risk X Proportion of population exposed.

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64
Q

What is attributable risk?

A

Attributable risk is the difference in risk between the exposed and the non-exposed.

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65
Q

Calculation for population attributable fraction?

A

PAF = Pe(RR - 1)/(1 + (Pe(RR - 1))), where Pe is the proportion of the population exposed to the factor and RR is the unadjusted relative risk of the outcome

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66
Q

What is the attributable risk?

A

Risk value attributable to exposure is the attributable risk.

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67
Q

How does one calculate the attributable risk?

A

. It is derived from obtaining the difference between control and experimental event rate.

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68
Q

Calculation for PAR?

A

It is derived from multiplying ARR from a study data with the proportion of a population that is exposed.

PAR = ARR X proportion of population exposed.

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69
Q

In which type of study is OR used?

A

Case control

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70
Q

What is incidence density sampling?

A

It involves matching each case to a set of individuals (usually >1) that are at risk of the exposure at the time of case occurrence.

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71
Q

What is needed in a study if the prevalence of a condition is low?

A

Larger sample size

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72
Q

What happens to sensitivity and specificity when two tests are used in sequence?

A

Loss in sensitivity

Gain in specificity

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73
Q

What happens to sensitivity and specificity if two tests are used in tandem?

A

Gain in sensitivity

Loss of specificity

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74
Q

What leads to high false positives?

A

Low-cut off

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75
Q

What happens if there is a high cut off for a disease?

A

Increased sensitivity
Decreased specificity
More false positives

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76
Q

What two things affect the predictive value?

A

Prevalence

If disease is rare - specificity

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77
Q

When do you want to avoid false negatives?

A

Deadly disease that has curative treatment i.e. can be treated early

78
Q

Calculation for post-test odds?

A

LR x pre-test odds

79
Q

What does 1-specificity refer to?

A

False positive rate

80
Q

Y axis of Kaplan-Meier curve?

A

Proportion of those who have not achieved the outcome of interest

81
Q

What is the hazard function?

A

the conditional probability of dying at time t having survived to that time.

82
Q

What can log rank test allow us to do?

A

Assess influence of categorical variable on survival

83
Q

What to use if we want to assess influence of continuous variable on survival?

A

Hazards/cox regression

84
Q

What tests are used for survival?

A

Cox regression

Log-rank (categorical data)

85
Q

What is the ‘hazard’ in Kaplan Meier curves/cox regression?

A

DV

86
Q

What is power?

A

Ability to detect true difference if it exists

87
Q

What affects power?

A

Sample size
Effect size being tested
Variability (SD)

88
Q

What is a surrogate outcome?

A

Any outcome that is easily measurable but used as a proxy for the actual primary outcome of direct benefit to patients.

89
Q

What is a composite endpoint?

A

Composite end points (CEPs) capture the number of patients experiencing any one of several adverse events— e.g. death, MI, or hospitalization—as a primary study endpoint.

90
Q

Reason to use composite endpoint?

A

to decrease the necessary sample size and duration of follow-up.
Uncertainty about single best outcome measure.

91
Q

Calculation for RRR

A

1 - (EER/CER)

92
Q

Unit of RRR

A

%

93
Q

What does RRR describe?

A

Reduction in events as a %

94
Q

What does ARR describe?

A

Reduction in people affected by the event i.e. size of the effect

95
Q

What happens to power if cluster sampling is used?

A

It is reduced

96
Q

What is used instead of sample size in cluster sampling?

A

Effective sample size

97
Q

What is used to calculate effective sample size?

A

Variance inflation factor/design effect derived from intracluster coefficient

98
Q

What is intracluster correlation?

A

Proportion of total variability of outcome measure attributed to between-cluster variability

99
Q

What does high intracluster correlation suggest?

A

All of the variability is due to between-cluster differences and responses within a cluster are highly correlated.

100
Q

How would you calculate CI using ARR?

A

Higher limit NNT = 1/lower limit of ARR

Lower limit of NNT = 1/higher limit of ARR

101
Q

Another name for a forest plot?

A

Blobbogram

102
Q

Name a measure of effect size

A

Cohens d

103
Q

What can be used to detect publication bias?

A

Funnel plot
Failsafe N
Galbraith plot
Comparing published vs unpublished data

104
Q

Calculation for accuracy

A

Add the two sets of true observations - true positive and true negative then divide by total sample size

105
Q

Define accuracy

A

The proportion of the sample that was correctly classified using the screening test.

106
Q

Calculation of attributable risk proportion

A

Incidence/incidence in exposed or

AR/EER

107
Q

Calculation for PAR

A

attributable risk x prevalence of exposure in the population

108
Q

Calculation for attributable risk percentage

A

AR/EER x 100

109
Q

Which study design is best for rare diseases?

A

Case-control

110
Q

Which study design can be used to study multiple risk factors?

A

Case-control

111
Q

In which type of study can incidence be calculated?

A

Cohort

112
Q

Difference between confounder and effect modifier?

A

a confounder distorts the relationship and produces an incorrect result.

effect modifier is a third factor that affects the magnitude of the cause-effect relationship.

113
Q

If crude risk differs from adjusted risk, what can one conclude?

A

the stratified factor is a confounder.

114
Q

If the relative risk of one stratum is different from other strata (subgroups) what can one conclude?

A

then we can call the factor an effect modifier.

115
Q

Difference between cost minimisation and cost benefits?

A

Cost minimisation: both scales looking at same outcome so both can be changed to monetary values

Cost benefit: between two outcomes with different scales which are represented in monetary terms

116
Q

In which economic analysis are the outcomes assumed to be equal and therefore only comparative cost is assessed?

A

Cost minimisation

117
Q

Does the denominator for incidence rate include those who already have the illness?

A

No

118
Q

What is the attack rate?

A

number of cases that develop divided by number exposed in a cohort (at risk). It is simply an incidence rate following an acute exposure.

119
Q

What type of bias does blinding aim to reduce?

A

Measurement bias

120
Q

What is it called when 2+ raters are used to analyse the data of Qualitative studies?

A

Triangulation

121
Q

What is sequential RCT?

A

the participants are recruited into each group until the investigators can clearly determine the difference or lack of difference between the groups. The sample size is not fixed a priori, and the analysis is regularly done , and the trial is stopped by a stopping rule, leading to a lower cost associated with the trial.

122
Q

What is intensity sampling?

A

Specifically picking a subject who is an expert in the topic

123
Q

What type of brain damage leads to working memory deficits?

A

Damage to genu of corpus callosum

124
Q

Risk fo Downs in someone who is 35 (mother)

A

1/350

125
Q

Risk of Downs in a 25 year old mother

A

1/1200

126
Q

Risk of Downs if mother is 40

A

1/100

127
Q

Risk of Downs if mother is 49

A

1/10

128
Q

Which therapy uses hypothetical and circumscribed questions?

A

Psychodynamic

129
Q

Difference between Tourettes and Chronic tic disorder?

A

In chronic tic disorder you have either motor OR vocal tics - not both

130
Q

Which MH problem is most common in Autism?

A

Social Anxiety

131
Q

1st line medication for ADHD in adults

A

Methylphenidate

132
Q

Which depot requires monitoring for 2 hours post-injection?

A

Olanzapine

133
Q

Early signs of opiate withdrawal?

A

agitation, anxiety, muscle aches, increased tearing, insomnia, runny nose, sweating, yawning.

134
Q

Late sx of opiate withdrawl?

A

abdominal cramping, diarrhoea, dilated pupils, goose bumps, nausea, vomiting.

135
Q

Which cognitive deficits are most often found in those with schizophrenia?

A

Working memory

136
Q

Which antipsychotic (2nd gen) can cause dysphagia in those with LD?

A

Olanzapine

137
Q

Best benzo to treat DT if cirrhosis?

A

Lorazepam

138
Q

Difference between methadone and buphrenorphine

A

Methadone doesnt have a ceiling effect, buprenorphine does

Methadone is best for patients dependent on high doses of opioids

139
Q

Most common parkinsonian sx secondary to antipsychotics?

A

Clasp knife rigidity
Rigidity
Bradykinesia

140
Q

Which family therapy gives homework assignments?

A

Strategic

141
Q

Which rec drug can cause UC?

A

Ketamine

142
Q

What medications can cause false positive for amphetamines?

A
Amantadine
Penicillin
Bupropion
Ephedrine
Phenothiazines
Ranitidine
Selegiline
Trazodone
Methylphenidate
Phenylphrine
143
Q

What drug causes false positive for benzos?

A

Sertraline

144
Q

What drugs cause false positive for Cannabis?

A

NSAIDs

PPIs

145
Q

What drug causes false positivies for cocaine?

A

Topical anaesthetics

146
Q

What drugs cause false positives for opioids?

A

Codeine & preparations e.g. cough mixture
Tonic water
Poppy seeds
Verapamil

147
Q

Prevalence of dystonia

A

10%

148
Q

Prevalence of pseudo-parkinsonism

A

20%

149
Q

Prevalence of akathisia

A

25%

150
Q

Prevalence of tardive dyskinesia

A

5%

151
Q

First chocie options for refractory depression

A
Add Lithium
Add T3
ECT
Combined use of olanzapine and fluoxetine
Add quetiapine to SSRI/SNRI
Add risperidone
Add aripiprazole
Bupropion & SSRI
SSRI & Venlafaxine/Mirtazapine/Mianserin
152
Q

Average suicide rate for the England

A

1 in 10,000

153
Q

Average suicide rate for mental health service users in England

A

1 in 1000

154
Q

Which medication is licensed for ADHD in adults?

A

Atomoxetine only

155
Q

Incidence of puerpural psychosis?

A

1 in 500

156
Q

Calculation for RRR?

A

RR-1

157
Q

Calculation for ARR?

A

PEER (patient expected event rate) or CER x RRR

158
Q

What is the non-parametric equivalent of ANOVA?

A

Kurskal-Wallis

159
Q

What is the non-parametric equivalent of repeated measures ANOVA?

A

Friedman test

160
Q

Which test compares two different interventions with two different clinical outcomes in terms of money?

A

Cost benefit

161
Q

What reliability is a measure of internal consistency of a test?

A

Split half reliability

162
Q

Define SEM

A

Dispersion of sample mean aorund true mean

163
Q

Risks to babies of mothers on Lithium during pregnancy

A
Ebsteins Anomaly
ASD
VSD
Neonatal goiter
Hypotonia
Lethargy
Cardiac arrhythmias
164
Q

Risk of septal heart defects in babies of mothers on citalopram?

A

2-2.5 fold increase

165
Q

Risk of PPH in babies of mothers on citalopram?

A

6 times greater

166
Q

Which ethnicity lacks one copy of functional CYP2D6?

A

East Asians

167
Q

Which disorders have low cortisol?

A

CFS
PTSD
Fibromyalgia

168
Q

Which meds increase lamotrigine levels?

A

Valproate

169
Q

Which meds decrease lamotrigine levels?

A

Oral contraceptives

Carbamazepine

170
Q

Which antipsychotic can cause myoclonic seizures?

A

Olanzapine

171
Q

Which age suggests good prognosis of anorexia?

A

Younger age

172
Q

1st line medication for kids with OCD

A

Sertraline

173
Q

How many children with depression later manifest bipolar?

A

20%

174
Q

How many <65 have FTD?

A

12%

175
Q

Which heroin replacement therapy is recommended for women breast-feeding?

A

Methadone

176
Q

During what time following cessation of alcohol is risk of seizure highest?

A

First 24 hours

177
Q

Prevalence of depression among patients with alcohol dependence?

A

25-30%

178
Q

What % of men in the UK drink above weekly limit?

A

26%

179
Q

What % of women in the UK drink above the weekly limit?

A

15%

180
Q

Prevalence of hazardous drinking in men

A

38%

181
Q

Prevalence of hazardous drinking in women

A

15%

182
Q

Which age group in women have highest level of drinking?

A

16-19 (32%)

183
Q

Which age group in men have highest level of drinking?

A

20-24 (62%)

184
Q

How is total alcohol consumption expressed?

A

By per capita consumption figures for people >15 years

It is the average amount of pure alcohol in litres consumed in 1 year

185
Q

How many adults in the UK smoke cannabis?

A

10%

186
Q

How many cannabis users are <24?

A

50%

187
Q

How many school children have used cannabis in the last year?

A

12%

188
Q

What is proportionate mortality rate?

A

Ratio between deaths due to specific cause and total deaths in population

189
Q

What is case fatality rate?

A

Number of deaths due to a disease and number of people affected by a disease

190
Q

What does I^2 value tell us?

A

% of variability in effect estimates that is due to heterogeneity