Open access Original research BMJ Open: first published as 10.1136/bmjopen-2018-028736 on 10 November 2019. Downloaded from Association of the frequency of spicy food intake and the risk of abdominal obesity in rural Chinese adults: a cross- sectional study Kaili Yang,1,2 Yuqian Li,3 Yuan Xue,4 Ling Wang,4 Xiaotian Liu,2 Runqi Tu,2 Xiaokang Dong,2 Zhenxing Mao,2 Wenjie Li,4 Chongjian Wang 2 To cite: Yang K, Li Y, Xue Y, et al. ABSTRACT Strengths and limitations of this study Association of the frequency Objectives Recent data relating to the association of spicy food intake and the between spicy food intake frequency and abdominal ► This is the first study to estimate the relationship risk of abdominal obesity in obesity are limited, especially in low-income areas. rural Chinese adults: a cross- between spicy food intake frequency and abdominal Therefore, the study explored the relationship between sectional study. BMJ Open obesity mediated by energy intake. spicy food intake frequency and abdominal obesity, and 2019;9:e028736. doi:10.1136/ ► A large, population- based sample was investigated. assessed the role of energy intake as a mediator of these bmjopen-2018-028736 ► The study included available information on a broad associations in a rural Chinese adult population. range of covariates. ► Prepublication history and Design Cross- sectional study. ► However, the survey did not clarify a relevant caus- additional material for this Setting Rural Chinese adult population. paper are available online. To al association between spicy food intake frequency Participants Subjects from Henan Rural Cohort Study view these files, please visit and abdominal obesity. the journal online (http:// dx. doi. (n=28 773). org/ 10. 1136/ bmjopen- 2018- Primary outcome measures The effects of spicy food 028736). intake frequency on abdominal obesity were analysed by 1 restricted cubic spline and logistic regression, and the diseases. Although great efforts have been Received 21 December 2018 mediation effect was analysed using the bootstrap method. made to control the weight of the popu- Revised 12 September 2019 Results The adjusted percentages of abdominal obesity lation in China, the prevalence of obesity Accepted 17 September 2019 were 47.32%, 51.93%, 50.66% and 50.29% in the spicy continues to increase, especially in the rural food intake subgroups of never, 1–2 day/week, 3–5 day/ 2 areas. According to the data obtained in the http://bmjopen.bmj.com/ week and 6–7 day/week, respectively. An inverse U- China Health and Nutrition Survey (CHNS) shaped association was found between spicy food intake in 2011, the prevalence of abdominal obesity © Author(s) (or their frequency and abdominal obesity (p<0.01). Compared was 44.0% in rural China.3 A recent study employer(s)) 2019. Re- use with subjects who never consumed spicy food, the also showed that the age-standardised prev- permitted under CC BY- NC. No adjusted ORs (95% CIs) in the 1–2 day/week, 3–5 day/ commercial re- use. See rights week and 6–7 day/week subgroups were 1.186 (1.093, alence of abdominal obesity was 43.71% in and permissions. Published by rural Chinese adults.4 Ongoing and reliable BMJ. 1.287), 1.127 (1.038, 1.224) and 1.104 (1.044, 1.169), programmes are needed to manage obesity 1Henan Provincial People’s respectively. Furthermore, the increased odd of abdominal Hospital, Henan Eye Hospital, obesity related to more frequent spicy food intake was and reduce the associated complications. It is on September 27, 2021 by guest. Protected copyright. Henan Eye Institute, People's mediated by higher fat energy intake; the direct and commonly acknowledged that many modifi- Hospital of Zhengzhou indirect effects were 1.107 (1.053, 1.164) and 1.007 able risk factors contribute to obesity besides University, Zhengzhou, China (1.003, 1.012), respectively. genetic factors. Physical activity and lifestyle 2 Department of Epidemiology Conclusions The data indicated that spicy food intake factors, particularly dietary behaviour, are and Biostatistics, College of increased the risk of abdominal obesity, and fat energy Public Health, Zhengzhou considered to be closely related to obesity, intake may be a mediator of this association in rural especially in low/middle- income countries.1 University, Zhengzhou, China Chinese populations. Clarifying the mechanisms will 3Department of Clinical Spices, which improve the flavour and taste facilitate the development of novel preventive and Pharmacology, School of therapeutic approaches for abdominal obesity. of food, have long been widely consumed Pharmaceutical Science, in Chinese cuisine.5 Several studies have Zhengzhou University, Trial registration number ChiCTR- OOC-15006699 Zhengzhou, China indicated that the consumption of spicy 4Department of Nutrition and food affects obesity-related human health Food Hygiene, College of Public INTRODUCTION outcomes, such as hypertension, irritable Health, Zhengzhou University, As a disorder of energy metabolism, obesity bowel syndrome, lipid disorders, cancers Zhengzhou, China is defined as abnormal or excessive fat accu- and even mortality.6–10 As the most practical Correspondence to mulation that may impair health, and the and simplest index, waist circumference is Dr Chongjian Wang; excessive accumulation of visceral fat is an used to measure the magnitude of fat accu- tjwcj2005@ 126. com independent risk factor of cardiovascular mulation in the abdomen. An observational Yang K, et al. BMJ Open 2019;9:e028736. doi:10.1136/bmjopen-2018-028736 1 Open access BMJ Open: first published as 10.1136/bmjopen-2018-028736 on 10 November 2019. Downloaded from study conducted in five urban and five rural areas of per week was selected by the participants. Based on the China provided evidence that the frequency of spicy food observation of the existing epidemiological studies,16 the consumption was positively associated with waist circum- participants were divided into four groups according to ference,11 which indicated that spicy food intake plays a spicy food intake frequency: never (reference), 1–2 day/ role in the regulation of abdominal obesity. According to week, 3–5 day/week and 6–7 day/week. The participants the sixth national population census, the rural districts were asked to confirm that the food types contained account for 63.90% of the population of China, and spices. The test–retest reliability and the internal consis- the education level, economic development, behaviour tency of the questionnaire were accredited through a factors, food choices and dietary patterns in rural areas pilot study with 76 subjects. The intraclass correlation differed from those found in urban areas of China.12 coefficient (ICC) was 0.978, which indicated that the However, the associations between spicy food intake current variable provides a reasonable estimation of spicy frequency and abdominal obesity in rural populations food intake frequency. remain to be fully elucidated. Furthermore, population studies have shown that spicy food consumption inhibits Assessment of covariates obesity by regulating energy metabolism,13 and Choi and Detailed information on sociodemographic and life- Chan14 found that the energy intake in chili pepper non- style factors was collected using a questionnaire. The users was significantly lower than that in chili pepper following variables were included in the current study: users in the New York City area. However, the associations age, gender, education, tobacco use (current smoker was among spicy food intake frequency, energy intake and defined as smoking at least one cigarette per day for six abdominal obesity have not been reported. consecutive months), alcohol use (current drinker was Therefore, the study investigated the effects of spicy defined as alcohol drinking of at least 12 times per year) food intake frequency on abdominal obesity in a rural and marital status. Individual dietary intake data were Chinese population, and assessed the role of energy collected by asking each household member to report intake as a mediator of these associations. the category of all food consumed, quantity, meal type and dining place) using a dietary recall method. The quantity of food consumed, including staple food, live- METHODS stock, poultry, fish, eggs, dairy, fruits, vegetables, beans, Study participants nuts, pickles, cereal and animal oil over the previous year The participants in the current study were from the was recorded. For each individual, the mean total daily Henan Rural Cohort Study.15Briefly, the study was energy intake and the proportions of protein, fat and carried out between July 2015 and September 2017 in carbohydrate were derived from dietary data according the following locations in Henan Province in China: to the Chinese Food Composition Table (2009). The Xuchang City, Yuzhou County; Zhumadian City, Suiping 3- day 24 hours record was conducted in a small sample http://bmjopen.bmj.com/ County; Kaifeng City, Tongxu County; Xinxiang City, to validate the FFQ and the results demonstrated that the Xinxiang County and Sanmenxia City, Yima County. A questionnaire provided a representative tool to conduct a 17 total of 29 867 people aged between 18 and 79 years and dietary evaluation of a rural population. Physical activity with complete information for spicy food intake and waist was divided into low, middle and high according to the 18 circumference measurements were recruited into the international physical activity questionnaire. Blood current study. To better estimate the relationship