根據網絡流傳的說法，印度人罹患癡呆症的比例，比許多國家的人民低。由於印度人嗜吃含有薑黃素的咖哩，而據說薑黃素的功效可以預防、治療阿茲海默症，方便抑制 β 類澱粉蛋白的聚合顆粒沉積在腦神經的間隙，從而避免傳導訊息的能力受阻，所以就有人斷定，多吃咖哩可以避免老年癡呆症的發生。
Misuse of statistics
Although we live in an era that emphasises data, the misuse of statistics is rampant, which can lead to the communication of erroneous messages. Here are some random examples.
There is a widely circulated online assertion that Indians have a lower rate of dementia than people from many other countries because curry contains curcumin. The theory is that curcumin decreases the accumulation of beta-amyloid plaque between nerve cells (neurons) in the brain, thus preventing the blocking of cell-to-cell signalling and reducing memory loss. This process can help to prevent and treat Alzheimer's disease (AD), the theory claims. However, the cognitive deficit in dementia is actually closely linked to age (or ageing). Indians have a comparatively short life expectancy (an average of 68 years compared to 84 years in Hong Kong). Thus, it is not surprising that there are fewer cases of dementia in India. Unless confirmed otherwise by more stringent research on the subject, the assertion that eating more curry helps prevent AD doesn't necessarily hold water.
People in Hong Kong, both men and women, have the longest average life expectancy in the world. But there is no consensus on the reasons for this. Some think it is because the Hong Kong diet is light and healthy. Hong Kong people tend to eat steamed fish, for example, which is healthier than fried fish. Others attribute it to Hong Kong's sound medical system and the habit of brewing herbal soups. Still others claim it is due to advanced internationalisation, the introduction of a Western education system, decreasing smoking rates, convenient transportation, or even feng shui. There may be some value to some or all of these claims in terms of quality of life and longevity, but they can hardly be considered as the fundamental reasons for the longevity of Hong Kong people.
In fact, the reason is more likely that Hong Kong people have superb genes for longevity, but somehow this is never mentioned. Looking back, we find that the majority of Hong Kong residents were originally immigrants who came from mainland China within the last hundred years. Successful immigrants either "bought" or "fought" their way in through talent and determination. Some had to overcome a multitude of difficulties, climbing mountains and swimming long distances to get to Hong Kong. Others managed to work their way into the Hong Kong police force or security guard field after passing scrupulous screening tests. These successful immigrants were not everyday people – they are perfect examples of "survival of the fittest". Therefore, it is not entirely coincidental that the survivors were healthier and more intelligent than average, and that their descendants have a longer life expectancy and higher IQ.
When I first went to study in the US, Americans were amazed at the intelligence, and grades, of Chinese students. Similarly, we read statistics demonstrating how Indian Americans, or Indo-Americans, are among the highest-paid Americans and therefore among the richest people in the world. But these phenomena are the result of comparisons based on biased samples. The Chinese studying in the US and the Indians immigrating to the US are not average citizens from those countries. Their excellence, therefore, is not surprising! We cannot claim that all Chinese or Indians are the smartest.
Another example of the misuse of statistics can be found in a recent news report revealing that Taiwan policemen seem to have the highest record of driving under the influence of alcohol among all professions. This has led to demands that these law-breaking policemen, who are supposed to uphold the law, should face a heavy double penalty.
This demand might sound reasonable at first glance. But careful examination of the data reveals a different picture. It turns out that policemen caught driving under the influence are obliged to report the incident, while people in other fields caught under the same circumstances are not. Therefore, the widely used comparison is completely invalid, like comparing apples with oranges.
Conclusions deduced from statistics without proper analysis are often misleading. Such fallacious conclusions can be found everywhere.
16 January, 2017