Accuracy of Body Weight Perception, Obesity Indicators, and Chronic Illness Among Chinese Americans

Shan Liu, PhD, RN, Assistant Professor, College of Nursing and Public Health, Adelphi University; Mei R. Fu, PhD, RN, FAAN, Tenured Associate Professor, NYU Rory Meyers College of Nursing, New York University; Sophia H. Hu, PhD, RN, Assistant Professor, School of Nursing, Taipei Medical University, Taipei, Taiwan. Vincent Y. Wang, MD Internal Medicine Office, 43-73 Union Street Suite C-B; Flushing; Robert S. Crupi, MD, Chief, Corporate Health & Wellness New York-Presbyterian/Queens

 

INTRODUCTION

The prevalence of obesity is increasing throughout the world. According to World Health Organization (WHO), worldwide obesity has nearly doubled since 1980 and 35% of adults aged 20 and over were overweight in 2008, and 11% were obese [1]. Chinese Americans make up the largest subgroup of Asian American and represent 4% of the total U.S. population. [2]. Compared to Chinese population in China, Chinese Americans have increased risk for obesity in the United States due to immigration and environmental change[3]. Obesity has been identified as a major source of unsustainable health costs, and morbidity and mortality due to hypertension, type 2 diabetes, cardiovascular diseases and certain types of cancer [4, 5].Accuracy of body weight perception is conceptualized as an individual’s perception of their body weight (normal weight, overweight, or underweight) in comparison with actual body weight [6]. Accuracy of body weight perception may be different in different ethnicities and cultures. No studies have examined the accuracy of perception of body weight among Chinese Americans. Body mass index (BMI) is a widely-used and conventional measure for evaluation of obesity [7]. However, research suggests established cut-points for classifying obesity with BMI may not apply to Asians and Asian Americans [8]. This article summarizes the following two publications:

Liu, S., Fu, M.R., Hu, S.,Wang, V.Y., Crupi, R., Qiu, J.M., Cleland, C., D’Eramo Melkus, G. (2015). Obesity Indicators and Chronic Illness among Chinese Americans: A Pilot Study. Journal of Obesity & Weight Loss Therapy, 5:4; http://dx.doi.org/10.4172/2165-7904.1000270.

Liu, S., Fu, M.R., Hu, S.,Wang, V.Y., Crupi, R., Qiu, J.M., Cleland, C., D’Eramo Melkus, G. (2015). Accuracy of Body Weight Perception and Obesity among Chinese Americans. Obesity Research & Clinical Practice. DOI: 10.1016/j.orcp.2015.04.004. Epub Ahead, May 1, 2015.

 

METHOD

The study was approved by the institutional review board of the university. A descriptive and cross-sectional study was conducted in a community health center in New York. Study participants were all Chinese-American adults, including both first generation and succeeding generations. Participants who came to the community health center for both routine health check-ups were invited to the study. The study invitation was distributed by physicians or nurses working in the community health center.

Data regarding demographic characteristics were collected to include age, gender, educational level, occupation, immigrant background (year of immigration, primary language), and living status (live alone, live with family, assistant living). By comparing participants’ perceived body weight category with their actual body weight category, participants were divided into 3 groups: consistent estimation (participants’ perceived body weight is consistent with their actual body weight), underestimation (participants’ perceived body weight is lighter than their actual body weight) and overestimation (participants’ perceived body weight is heavier than their actual body weight).Weight was measured by an electronic scale to the nearest 0.01 kg. Height was measured by a portable stadiometer to the nearest 0.1 cm. A flexible and inelastic tape was used to measure waist circumference (WC) and hip circumference (HC). Three measurements of WC and HC were obtained to compute the mean values. Body Mass Index (BMI) was calculated based on a ratio between body weight and height: BMI = weight (lb) / height (inches) x 703. Actual body weight was categorized into three types according to the BMI cutoff points based on the recommendations from WHO and Asian American Diabetes Center [9, 10]: underweight (BMI<18.5), normal (18.5=<BMI<=23.9), overweight (BMI>24). Data regarding fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1C) were collected from the latest lab data within 90 days. Chronic ilnesses, such as hypertension, diabetes, heart disease and stroke, were verified by reviewing each participant’s medical record.

 

RESULTS

Demographic Characteristics of Participants

A total of 162 Chinese American were recruited from January to July 2012. Among 162 participants, 32 participants were categorized in the group of underestimation, that is, participants’ perceived body weight was lighter than their actual body weight; 20 participants in overestimation group, that is, their perceived body weight was heavier than their actual body weight; and 110 participants had consistent/accurate estimation, that is, participants’ perceived body weight was consistent with their actual body weight. Among 162 Chinese American who were recruited, 94 participants had fewer than three chronic illnesses and 68 participants had three or more chronic illnesses.

Significant differences were found among participants in three groups of different accuracy of body weight perception in terms of gender (p=0.003), age (p=0.003), and education years (p=0.047). In the underestimation group, men had 2.34 times more odds than women to think that they were under the normal weight (OR=2.34, 95% CI 1.01-5.43). In the overestimation group, women had 3.59 times more odds to think that they were over the normal weight (OR=3.59, 95% CI 1.13-11.42). Participants in the overestimation group were significantly 13 years younger than participants in the underestimation group (p=0.003, 95% CI 4.07-23.27) and 14 years younger that participants in consistent/accurate estimation group (p=0.007, 95% CI 3.46-24.12). Participants in the underestimation group had significantly 3.2 less years of education than those in the overestimation group (P=0.04, 95% CI 0.11-6.21).

 

 

Multiple Chronic Illnesses

Among 162 participants, 91.2% has at least one of chronic illnesses. The three most common chronic illness in this population was diabetes (65.4%), hypertension (46.9%), and eye problem (38.3%), followed by foot problem (16.7%), skin problem (16.0), and heart disease (15.4%). The mean number of chronic illness was 2.88, with the range from 0 to 9.

 

Obesity Indicators

The average BMI of participants was 24.3 (Mean + SD: 24.3+ 3.9), waist circumference (WC) 84.3cm (Mean +SD: 84.3+ 10.2), hip circumference (HC) 94. 9cm (Mean +SD: 94.9+ 9.1), waist/height ratio 51.7 (Mean +SD: 51.7+ 5.9) and waist/hip ratio 0.89 (Mean +SD: 0.89+ 0.07). Participants in consistent estimation group and underestimation group had similar WC HC and weight/height ratio, but much higher than the participants in overestimation group. Controlling for all demographic confounders, accuracy of perception of body weight continued to have significant relationships with obesity indicators. Accuracy of perception of body significantly predicted WC (p<.001), HC (p<.001), weight to height ratio (p=0.001), BMI (p<.001) and weight (p<.001). In addition, participants with three number of chronic illness or more had 5cm bigger WC (p=0.001), 4cm bigger HC (p=0.001), 3.8 more weight/height ratio (p=0.000), 0.7 more HbA1C, 18 more FPG. Controlling for all demographic confounders, number of chronic illness continued to have significant associations with obesity indicators. WC (p=0.006), HC (p=0.020), weight to height ratio (p=0.011), HbA1C (p=0.026) significantly predicted whether the number of chronic illness was more than three or not.

 

Obesity related Physical Characteristics and Chronic Illness

For HbA1C, overestimation group had lower HbA1c (5.7+ 0.4) than both consistent/accurate estimation (6.3+ 1.0) and underestimation (6.5+ 1.7) groups (p=0.004). However, when controlling for demographic confounders, accuracy of perception of body weight was no longer related to HbA1c. Accuracy of perception of body weight was also not related with chronic illnesses including hypertension and heart diseases. On the other hand, all obesity indicators in this study significantly associated with diabetes, except weight. Participants with increasing WC, HC, weight to hip ratio, weight to height ratio, BMI, HbA1C, FBS had increasing risks for diabetes. Associations between obesity indicators and hypertension were exactly the same as the association between obesity indicators and diabetes. Participants with increasing WC, HC, as well as weight to height ratio had increasing risks for heart disease. While all other obesity indicators were not associated with eye problems and foot problems, HbA1C had the significant associations. Participants with increasing HbA1C were more likely to have eye problems and foot problems.

 

DISCUSSION

The results of this study added to the literature by assessing the concept of accuracy of body weight perception, and relationship between chronic illness and obesity indicators in Chinese American for the first time. In our study, one third of the participants did not perceive their body weight status correctly could suggest that future studies for obesity management for Chinese American should examine how many patients have inaccurate perception of body weight, since perception of body weight status has been reported to be associated with efforts of losing weight and weight-related behaviors[6, 11].

The majority of the participants in this study had diabetes (65%), and around half of the population had hypertension (46.7%). The percentages of diabetes and hypertension in our study were higher that what were in the literature. Possible reason could be that many participants in this study were recruited from a community center specialized in diabetes care, therefore many patients with diabetes and/or hypertension were recruited. Another reason could be that old age and long immigration time in this population increased the risk for obesity-related chronic illness.

Many obesity indicators in this study had significant associations with number of chronic illnesses. Patients with increasing WC, HC, BMI, weight to height ratio were more likely to more multiple chronic illnesses. Obesity has been reported to be a risk factor for morbidity and mortality of many health problems [12, 13]. In Chinese Americans, measuring both general and central adiposity to classify and quantify obesity and obesity-related risks are necessary [12]. Our study showed that WC, HC and weight to height ratio remained to be predictors for increased number of chronic illness, which BMI lost the significant prediction, after controlling other significant factors such as age (P<0.001), marital status (P<0.001). This finding was consistent with the part of the literature that measurement of central obesity indicators were more sensitive obesity indicators [14].

Accuracy of body weight perception was found to be an interesting indicator for obesity in our study. Gender difference was obvious. Male Chinese Americans were more likely to underestimate their weights while female were more likely to overestimate their weights. The finding of this study suggests that obesity research studies for Chinese American should pay attention to gender difference. In this study, younger Chinese Americans were more likely to overestimate their weight. The association of age and perception of body weight in our study suggested that the elderly Chinese Americans, majority of whom was in the consistent estimation & underestimation group in our study, may need more targeted intervention to manage weight.

In our study, all three body perception groups had higher BMI (>=23kg/m2) and consistent estimation and under estimation group have higher WC (>=85cm), indicating the need of intervention studies to lost weight for obesity in the Chinese Americans. When examining the relationship between perception of body weight accuracy and obesity indicators, our study showed that the perception of body weight in Chinese Americans were significantly associated with obesity indicators including WC, HC, weight, BMI and weight to height ratio, even after controlling for all demographic confounders. In this study, participants in both consistent estimation group and underestimation group had significantly much higher WC, HC than those in overestimation group. Accordingly, future interventions might focus on educating Chinese Americans normal and obese WC&HC values to promote accurate perception of weight status, thus to improve the weight-related behaviors for this group.

 

Conclusion

This is the first study that examines the accuracy of body weight perception in Chinese Americans and the relationship between obesity indicators and chronic illnesses among Chinese Americans. The study identifies around one third of Chinese American did not perceive their body weight correctly. The study also found that accuracy of body weight perception was associated with several demographic factors including gender, age, education, obesity related indicators such as waist circumference [WC], hip circumference [HC], weight to height ratio, and BMI. The study could lay a good foundation for future possible intervention studies for obesity management in the minority group of Chinese American. The study also identifies both general obesity (BMI) and central obesity indicators (WC HC, and weight to height ratio) are associated with increased numbers of chronic illnesses, controlling for other demographic factors, and HbA1C had strong relationship with multiple chronic illnesses including diabetes, hypertension, heart diseases, and eye and foot problems. Given the small sample size in this study, future research with larger sample size are needed to verify the results of this study.

 

Acknowledgments

This research was supported by a research grant awarded by NYU Pless Center of Nursing Research, Association of Chinese American Physicians, and the National Institute of Health (NIMHD Project # P60 MD000538-03). Its contents are solely the responsibility of the authors and do not necessarily represent the funders. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscripts.

 

Corresponding Author

Mei R. Fu, PhD, RN, FAAN

College of Nursing, New York University, 433 First Avenue, 4th Floor, Room 424, New York City, New York, USA; 10010

Tel: 212-998-5314

Fax: 212-995-3143
Email: mf67@nyu.edu

 

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