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RE: st: R: Adjusting prevalences
From
Miguel Ângelo Costa <[email protected]>
To
"[email protected]" <[email protected]>
Subject
RE: st: R: Adjusting prevalences
Date
Wed, 10 Jul 2013 17:25:40 +0000
Dear all,
After some research I ended up realizing that the svy command would probably sort this out. I never used this before though, so could you please tell me if I'm doing this right?
Here's what I've done:
1. created a categorical age variable with 10y interval between categories (age_categ_w)
2. created a variable with the proportion of each age category in the whole sample (std_wgt)
3. since there were no strata I was interested in I ran .svyset _n
4. ran .svy, subpop(if analysis == 1) : mean stage_0, stdize(age_categ_w) stdweight(std_wgt) over(sex) to get the age-adjusted prevalences over gender. variable stage_0 is the variable that codes the presence/absence of the condition, ofc.
result is
(running mean on estimation sample)
Survey: Mean estimation
Number of strata = 1 Number of obs = 2975
Number of PSUs = 2975 Population size = 2975
N. of std strata = 5 Subpop. no. obs = 2975
Subpop. size = 2975
Design df = 2974
Female: sex = Female
Male: sex = Male
--------------------------------------------------------------
| Linearized
Over | Mean Std. Err. [95% Conf. Interval]
-------------+------------------------------------------------
stage_0 |
Female | .7427175 .0106132 .7219076 .7635274
Male | .8063201 .0108967 .7849542 .8276859
--------------------------------------------------------------
Am I [doing this right]?
Thank you
Miguel
> From: [email protected]
> To: [email protected]
> Subject: st: R: Adjusting prevalences
> Date: Mon, 8 Jul 2013 12:56:48 +0200
>
> As far as 2nd Miguel Ângelo's question is concerned, he can probably benefit
> from taking a look at:
>
> [R] poisson -- Poisson regression, by typing - help poisson - from within
> Stata.
>
> [R] poisson entry is included in Stata 12.1 .pdf manual.
>
> Kind regards,
> Carlo
> -----Messaggio originale-----
> Da: [email protected]
> [mailto:[email protected]] Per conto di Miguel Ângelo
> Costa
> Inviato: lunedì 8 luglio 2013 12:25
> A: [email protected]
> Oggetto: st: Adjusting prevalences
>
> Hi,
>
> In the data analysis of an epidemiological cross-sectional study I'm
> calculating prevalences.
>
> The dataset is pretty standard. Something like this:
>
> patnumber sick (1-sick 0-nonsick) disease-stage risk-factor-1
> risk-factor-2 risk-factor-3 age
> 0001 1 1 1 0 1 60
> 0002 0 0 0 1 80
> 0003 1 2 0 0 0 75
> etc...
>
>
> I have been making two way tabulations to calculate frequencies of disease
> per age categories and disease-stage per age categories, etc... and then
> calculating prevalences semi-manually with matrices.
>
> question 1: Do you know of any Stata module that can facilitate this?
> questino 2: I want to adjus the prevalences for risk-factors and age...how
> would you do it?
>
>
> Thank you for your help
>
> Best regards
> Miguel Ângelo Costa
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