Annals of Internal Medicine的编辑发表了一篇附带的评议，指出虽然咖啡的品质可以使健康受益，但混杂的变量包括更难测量的社会经济地位、饮食和其他生活方式因素的差异可能会影响研究结果。作者补充说，参与者的数据至少是10年前的，而且是从一个茶叶更主流流行饮料的国家收集的。他们提醒说，这项分析中记录的每杯咖啡的平均日糖量比流行的咖啡连锁店的特色饮料要低得多，而且许多咖啡消费者可能用它来代替其他饮料，这使得与非饮酒者进行比较更加困难。
Previous studies looking at the health effects of coffee have found that coffee drinking is associated with a lower risk of death, but there is no distinction between unsweetened coffee and coffee with sugar or artificial sweeteners. The researchers found that those who drank 1.5 to 3.5 cups of sugary coffee a day were 29% to 31% less likely to die than those who did not drink coffee.
Researchers from Southern Medical University in Guangzhou, China, used data from the British Biobank Research Health behavior questionnaire to assess the relationship between consumption of sweetened, artificially sweetened and unsweetened coffee and all-cause and specific cause mortality. More than 171000 participants from the UK who had no known heart disease or cancer were asked several dietary and health behaviour questions to determine coffee consumption habits.
The authors found that participants who drank any amount of sugar-free coffee were 16% to 21% less likely to die during a 7-year follow-up period than those who did not drink coffee. They also found that participants who drank 1.5 to 3.5 cups of sweetened coffee a day were 29% to 31% less likely to die than those who did not drink coffee. The authors point out that adults who drink sweetened coffee add only about 1 teaspoon of sugar per cup of coffee. For participants who used artificial sweeteners in coffee, the results were uncertain.
The editors of the Annals of Internal Medicine published an accompanying review pointing out that while the quality of coffee can benefit health, mixed variables including differences in socioeconomic status, diet and other lifestyle factors that are more difficult to measure may affect the findings. The authors added that the participants' data were collected at least 10 years ago and were collected from a country where tea is more popular. They cautioned that the average daily sugar content per cup of coffee recorded in the analysis was much lower than that of specialty drinks in popular coffee chains, and that many coffee consumers might use it instead of other drinks, making it more difficult to compare with non-drinkers.
Based on these data, clinicians can tell their patients that most coffee drinkers do not need to eliminate the drink from their diet on health grounds, but should be cautious about high-calorie specialty coffee drinks.