面对阴性的大量数据，也许，你还会有新的发现，所需要做的可能就是进一步细分你的目标群。
http://www.medscape.com/viewarticle/731251?src=mp&spon=30&uac=102405PJ
October 27, 2010 — High vegetable consumption is associated with a significantly lower risk for estrogen receptor-negative/progesterone receptor-negative (ER-/PR-) breast cancer in black women, according to results from the Black Women's Health Study reported online October 11 in the American Journal of Epidemiology. However, there was no association of total fruit/vegetable intake with overall breast cancer risk, and the investigators suggest that their significantly positive finding of a lower risk for ER-/PR- breast cancer could possibly be due to chance as a result of multiple comparisons.
"This is an important finding because if confirms what we had seen earlier in our cohort of registered nurses who are predominantly white, specifically that higher intake of vegetables is associated with lower risk of ER- breast cancer," Walter Willett, MD, DrPH, chair of the Department of Nutrition at Harvard School of Public Health in Boston, Massachusetts, told Medscape Medical News when asked for independent comment. "If this is seen in just one study, we can't be confident that the results are not due to chance, but this finding provides strong support that this is real."
Deborah A. Boggs, from Slone Epidemiology Center at Boston University in Boston, Massachusetts, and colleagues prospectively evaluated the association of fruit and vegetable intake with breast cancer risk in a cohort of 51,928 women aged 21 to 69 years in 1995 when they enrolled in the Black Women's Health Study. The investigators used a validated food frequency questionnaire to determine dietary intake and Cox proportional hazards models to estimate incidence rate ratios and 95% confidence intervals (CIs), which were adjusted for breast cancer risk factors.
There were 1268 incident cases of breast cancer during 12-year follow-up. Dietary consumption of total fruits, total vegetables, and total fruit and vegetables was not significantly associated with the overall risk for breast cancer. However, total vegetable intake was linked to a lower risk for ER-/PR- breast cancer. For at least 2 vegetable servings per day vs less than 4 servings per week, the incidence rate ratio for ER-/PR- breast cancer was 0.57 (95% CI, 0.38 - 0.85; P for trend = .02).
There was also some evidence of inverse associations with overall breast cancer risk for cruciferous vegetable intake (P for trend = .06) and for carrot intake (P for trend = .02). Therefore, the investigators suggest that frequent consumption of vegetables is inversely associated with the risk for ER-/PR- breast cancer, and that intake of specific vegetables may be associated with a reduced risk for breast cancer overall.
"So far, there has not been much identified that women could do to reduce their risk of ER negative breast cancer, but this provides evidence that regular consumption of vegetables is likely to help," Dr. Willett said. "It will be important to examine this relation in additional populations and to focus more detail on the specific types of vegetables that could be beneficial."
Limitations of this study include possible misclassification of long-term dietary intake, which would likely be random and would have attenuated true associations, and possible confounding by unknown lifestyle factors. However, the study authors noted that they were able to control for several established breast cancer risk factors, which did not appreciably affect the results.
"Because we examined a large number of associations in these analyses, it is more likely that a given significant finding may be due to chance, and our results need to be confirmed," the study authors write. "Future studies investigating the association between subclasses of vegetables and subtypes of breast cancer are warranted."
The National Cancer Institute supported this study. The content of the study article is solely the responsibility of the authors and does not necessarily reflect the official views of the National Cancer Institute or the National Institutes of Health. The study authors and Dr. Willett have disclosed no relevant financial relationships.
Am J Epidemiol. Published online October 11, 2010. Abstract
[CLOSE WINDOW]
Authors and Disclosures
Journalist
Laurie Barclay, MD
Freelance writer and reviewer, Medscape, LLC
Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.
－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
曾经，有一个阶段试验数据很不稳定，现在想来，可能与不同来源的动物、不同周龄的动物不无关系，谁知道呢。
谁知道阴性结果中蕴含着多少阳性结果呢，甚至可以让你拿个高SCI。
细分试验动物,目前除非你自己生产动物,外买的试验动物很难有保证.
试验动物的周龄对某些试验的影响特别大,如抗衰老等
找个统计专家来，假阴性结果的可能性，让他喷死你
不做评论。
统计学本身就是概率的学科。一堆数据里发现一两个有显著意义的结果完全有可能。
p＝0.02本身就意味着有假阳性的可能是2％，如果再分析这个假阳性可能性的95％CI，你会发现更高的概率。
黑人女性，摄入植物性食物，乳腺癌完了还得是ER-/PR-的乳腺癌，还不知道背后有多少confounding factor呢，随便猜猜：
美国估计新鲜蔬菜比肉贵，所以蔬菜吃得多的收入比较高
蔬菜吃的多的估计比较注意健康的生活方式，可能运动也比较多
蔬菜吃的多的估计总体上比蔬菜吃的少的经济社会地位高，相应的受教育高、结婚生育晚
蔬菜吃的多的可能BMI比较低
.......
顺便说一下，流行病学研究，不太用p值，意义不那么大，常用RR或OR，而且RR>2才有相当大的意义，道理很简单，混淆因素太多，RR 1点几的意义可疑。
现在统计学真的很有意思，需要把微弱的信号从大量嘈杂背景中分开，这是何等的艰难。
细分人群只能给一些假设的灵感。要得到一个肯定的结果，还需要进行假设验证--设计一个有统计学效能的前瞻性研究。
这个是硬道理。
http://www.medscape.com/viewarticle/731251?src=mp&spon=30&uac=102405PJ
October 27, 2010 — High vegetable consumption is associated with a significantly lower risk for estrogen receptor-negative/progesterone receptor-negative (ER-/PR-) breast cancer in black women, according to results from the Black Women's Health Study reported online October 11 in the American Journal of Epidemiology. However, there was no association of total fruit/vegetable intake with overall breast cancer risk, and the investigators suggest that their significantly positive finding of a lower risk for ER-/PR- breast cancer could possibly be due to chance as a result of multiple comparisons.
"This is an important finding because if confirms what we had seen earlier in our cohort of registered nurses who are predominantly white, specifically that higher intake of vegetables is associated with lower risk of ER- breast cancer," Walter Willett, MD, DrPH, chair of the Department of Nutrition at Harvard School of Public Health in Boston, Massachusetts, told Medscape Medical News when asked for independent comment. "If this is seen in just one study, we can't be confident that the results are not due to chance, but this finding provides strong support that this is real."
Deborah A. Boggs, from Slone Epidemiology Center at Boston University in Boston, Massachusetts, and colleagues prospectively evaluated the association of fruit and vegetable intake with breast cancer risk in a cohort of 51,928 women aged 21 to 69 years in 1995 when they enrolled in the Black Women's Health Study. The investigators used a validated food frequency questionnaire to determine dietary intake and Cox proportional hazards models to estimate incidence rate ratios and 95% confidence intervals (CIs), which were adjusted for breast cancer risk factors.
There were 1268 incident cases of breast cancer during 12-year follow-up. Dietary consumption of total fruits, total vegetables, and total fruit and vegetables was not significantly associated with the overall risk for breast cancer. However, total vegetable intake was linked to a lower risk for ER-/PR- breast cancer. For at least 2 vegetable servings per day vs less than 4 servings per week, the incidence rate ratio for ER-/PR- breast cancer was 0.57 (95% CI, 0.38 - 0.85; P for trend = .02).
There was also some evidence of inverse associations with overall breast cancer risk for cruciferous vegetable intake (P for trend = .06) and for carrot intake (P for trend = .02). Therefore, the investigators suggest that frequent consumption of vegetables is inversely associated with the risk for ER-/PR- breast cancer, and that intake of specific vegetables may be associated with a reduced risk for breast cancer overall.
"So far, there has not been much identified that women could do to reduce their risk of ER negative breast cancer, but this provides evidence that regular consumption of vegetables is likely to help," Dr. Willett said. "It will be important to examine this relation in additional populations and to focus more detail on the specific types of vegetables that could be beneficial."
Limitations of this study include possible misclassification of long-term dietary intake, which would likely be random and would have attenuated true associations, and possible confounding by unknown lifestyle factors. However, the study authors noted that they were able to control for several established breast cancer risk factors, which did not appreciably affect the results.
"Because we examined a large number of associations in these analyses, it is more likely that a given significant finding may be due to chance, and our results need to be confirmed," the study authors write. "Future studies investigating the association between subclasses of vegetables and subtypes of breast cancer are warranted."
The National Cancer Institute supported this study. The content of the study article is solely the responsibility of the authors and does not necessarily reflect the official views of the National Cancer Institute or the National Institutes of Health. The study authors and Dr. Willett have disclosed no relevant financial relationships.
Am J Epidemiol. Published online October 11, 2010. Abstract
[CLOSE WINDOW]
Authors and Disclosures
Journalist
Laurie Barclay, MD
Freelance writer and reviewer, Medscape, LLC
Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.
－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
曾经，有一个阶段试验数据很不稳定，现在想来，可能与不同来源的动物、不同周龄的动物不无关系，谁知道呢。
谁知道阴性结果中蕴含着多少阳性结果呢，甚至可以让你拿个高SCI。
细分试验动物,目前除非你自己生产动物,外买的试验动物很难有保证.
试验动物的周龄对某些试验的影响特别大,如抗衰老等
找个统计专家来，假阴性结果的可能性，让他喷死你
不做评论。
统计学本身就是概率的学科。一堆数据里发现一两个有显著意义的结果完全有可能。
p＝0.02本身就意味着有假阳性的可能是2％，如果再分析这个假阳性可能性的95％CI，你会发现更高的概率。
黑人女性，摄入植物性食物，乳腺癌完了还得是ER-/PR-的乳腺癌，还不知道背后有多少confounding factor呢，随便猜猜：
美国估计新鲜蔬菜比肉贵，所以蔬菜吃得多的收入比较高
蔬菜吃的多的估计比较注意健康的生活方式，可能运动也比较多
蔬菜吃的多的估计总体上比蔬菜吃的少的经济社会地位高，相应的受教育高、结婚生育晚
蔬菜吃的多的可能BMI比较低
.......
顺便说一下，流行病学研究，不太用p值，意义不那么大，常用RR或OR，而且RR>2才有相当大的意义，道理很简单，混淆因素太多，RR 1点几的意义可疑。
现在统计学真的很有意思，需要把微弱的信号从大量嘈杂背景中分开，这是何等的艰难。
细分人群只能给一些假设的灵感。要得到一个肯定的结果，还需要进行假设验证--设计一个有统计学效能的前瞻性研究。
这个是硬道理。