Sugar sweetened beverages and endometrial cancer.
Endometrial cancer is one of the more prevalent cancers and is a common cause of cancer death worldwide. Factors that increase oestrogen exposure have been associated with an increasing risk of endometrial cancer such as greater body fatness, postmenopausal oestrogen therapy, late menopause and nulliparity. Whilst these risk factors have been mostly associated with type I-oestrogen dependent endometrioid tumours, the relationship with type II endometrial cancers remain less clear. Diabetes and obesity have also been associated with increasing risk of endometrial cancer, and with consumption of sugar-sweetened beverages (SSB), the leading source of added sugars in the US diet, being associated with a higher risk of obesity and type 2 diabetes, a biologically plausible link between SSB consumption and risk of endometrial cancer was explored by study authors in a study published in Cancer Epidemiology, Biomarkers & Prevention. Specifically, the association between dietary intake of SSB, other sugar-rich food groups and sugars and the risk of type I and type II endometrial cancers amongst postmenopausal women was evaluated.
This prospective cohort study among postmenopausal women used data from the Iowa Women's Health Study (IWHS) in which 41,836 women provided information through a self-administered survey assessing demographics, anthropometry, reproductive and lifestyle factors, family history of cancer, medical history and dietary intake that was mailed to randomly selected women aged 55-69 years in 1986.
Dietary intake was assessed using the Harvard Food Frequency Questionnaire (FFQ), which involved reporting the usual intake frequency of 127 food items during the past 12 months. A typical portion size for each food item was provided to guide participants. The FFQ included four questions specific to usual intake frequency of SSB, a question specific to 'sugar-free soft drinks' and addressed other added sugar intake through a 'sweets and baked goods' category comprising of 13 questions. Anthropometry data collected included weight and height, used to calculate BMI, and waist and hip measurements to calculate waist-hip ratio (WHR).
The IWHS cohort has been followed for vital status and cancer incidence annually and data from the cohort baseline until 31st December 2010 was used for the current analysis. Endometrial cancers identified were classified into type I and type II.
From the IWHS participants, 23,039 women were included in the current study with survey responders excluded if at cohort baseline (time of completion of the original survey) there was a history of cancer (except non-melanoma skin cancer), history of hysterectomy, incomplete dietary information, or extreme dietary intake defined as <600 or >5000kcal/day. Additionally, women were excluded if diagnosed with endometrial cancer in situ (n = 21) and sarcoma (n = 10) during follow up.
During the follow-up, researchers identified a total of 592 invasive endometrial cancers (506 type I and 89 type II) reported between 1986 and 2010. The mean ages were 72.6 years and 74.4 years for type I and type II respectively. Older age, higher BMI, higher WHR, history of diabetes, early menarche, delayed menopause, and oestrogen use were associated with higher risk of endometrial cancer whilst women who never smoked or who experienced greater number of live births were at lower risk of endometrial cancer.
Women who reported higher consumption of SSB were at higher risk of type I endometrial cancer in a dose-dependent manner. Compared with non-consumers of SSB, women who reported the highest consumption of SSB had a 78% increased risk of type I endometrial cancer. Fruit juice consumption in isolation was not associated with increased risk of type I endometrial cancer, however when fruit juice intake was added to SSB intake, the risk of type I endometrial cancer was 38% higher in the highest consumption group than in the lowest consumption group. These associations became stronger after adjusting for BMI, thus suggesting factors other than body weight may be involved in the link between SSB and type I endometrial cancer. No associations were identified between type I endometrial cancer and sugar-free beverage intake, sweet/baked goods consumption, nor starch intake. The risk of type II endometrial cancer was not associated with intake of SSB and sugars.
There are several limitations to the study. There is potential for recall bias and misclassification of dietary exposures through the dietary intake assessment of the FFQ. The associations were based on dietary information that was collected in 1986, and it is likely that dietary intake changes would occur over time. Additionally, the influence on the findings of confounding by-factors relating to SSB consumption and sugar consumption including body weight, physical activity, diabetes and cigarette smoking cannot be ruled out.
In the USA, high-fructose corn syrup (HFCS) is the major sweetener added to SSB whereas this is not the case in other parts of the world. In Sweden, sucrose is the major sweetener added to soft drinks and a Swedish prospective cohort study reported that risk of endometrial cancer did not differ between SSB drinkers and nondrinkers. As such, extrapolating the current findings that postmenopausal women who consume SSB were more likely to develop type I endometrial cancer compared to non-consumers of SSB in countries which do not use HCFS as a major sweetener should be done with caution.
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|Publication:||Australian Journal of Herbal Medicine|
|Date:||Jun 1, 2014|
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