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partizan_1812 May 18 2012, 02:31:06 UTC
А почему не верите?
Курение, я уверен, было и в контрольной группе.
Потребление кофе вроде не коррелирует с курением.

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nighttime_notes May 18 2012, 02:42:18 UTC
During 5,148,760 person-years of follow-up between 1995 and 2008, a total of 33,731 men and 18,784 women died. In age-adjusted models, the risk of death was increased among coffee drinkers. However, coffee drinkers were also more likely to smoke, and, after adjustment for tobacco-smoking status and other potential confounders, there was a significant inverse association between coffee consumption and mortality. Adjusted hazard ratios for death among men who drank coffee as compared with those who did not were as follows: 0.99 (95% confidence interval [CI], 0.95 to 1.04) for drinking less than 1 cup per day, 0.94 (95% CI, 0.90 to 0.99) for 1 cup, 0.90 (95% CI, 0.86 to 0.93) for 2 or 3 cups, 0.88 (95% CI, 0.84 to 0.93) for 4 or 5 cups, and 0.90 (95% CI, 0.85 to 0.96) for 6 or more cups of coffee per day (P<0.001 for trend); the respective hazard ratios among women were 1.01 (95% CI, 0.96 to 1.07), 0.95 (95% CI, 0.90 to 1.01), 0.87 (95% CI, 0.83 to 0.92), 0.84 (95% CI, 0.79 to 0.90), and 0.85 (95% CI, 0.78 to 0.93) (P<0.001 for trend). ( ... )

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partizan_1812 May 18 2012, 12:53:54 UTC
Докладываю, т.е. выкладываю ( ... )

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nighttime_notes May 18 2012, 14:10:13 UTC
Меня смущает отсутствие income. К тому же я не понимаю, как именно они adjusted - можно очень по-разному делать эти регрессии.
Вы могли бы скопировать только регрессию(и), которую(ые) они делают, с перечислением переменных? (Если это долго, то не стоит, конечно).

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partizan_1812 May 18 2012, 15:29:38 UTC
Дайте емелю в личку, я Вам пошлю pdf.
Описания статистики там нет, только в ссылках, но сами посмотрите.

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nighttime_notes May 18 2012, 17:11:30 UTC
Спасибо!

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partizan_1812 May 18 2012, 13:07:11 UTC
Продолжение
(из обсуждения в статье)

Авторы не наивные и понимают, что кофепитие м.б. связано с пониженной смертностью и не напрямую, но эта связь наблюдается (и еще сильнее) среди некурящих.

Several explanations for our findings are possible. As in all observational studies, associations could reflect confounding by unmeasured or poorly measured confounders. Although coffee consumption was inversely associated with diabetes, it was also positively associated with a number of behaviors that are considered unhealthy and are associated with an increased risk of death, such as tobacco smoking (35) consumption of red meat,36 and heavy alcohol use (37). Tobacco smoking was the strongest confounder in the multivariate analysis, and the inverse association between coffee consumption and mortality tended to be stronger among persons who had never smoked or were former smokers than among those who were current smokers, suggesting that residual confounding by smoking status, if present, attenuated the inverse associations between coffee ( ... )

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nighttime_notes May 18 2012, 02:46:41 UTC
В комментариях тоже хорошие вопросы, от статистической значимости эффекта до того, насколько эндогенно желание пить много кофе в зависимости от здоровья.

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tanyakuz May 18 2012, 03:37:53 UTC
Статистическая значимость у них есть - при таком-то количестве данных! (там полмиллиона человек участвовало в опросе). А вот то, что они не учитывают доход и род занятий, это ни в какие ворота не лезет.

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nighttime_notes May 18 2012, 14:05:47 UTC
Ну, в omitted variables можно любой значимости добиться :))

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