Prevalence and factors associated with overweight, obesity and central obesity among adults in Shenmu City, Shaanxi Province, China

Objectives This research aimed to explore the prevalence and determinants of overweight, obesity, and central obesity in Shenmu City, Shaanxi Province, China and to offer guidance for preventative health measures. Methods We conducted a multi-stage, stratified random sampling survey among 4,565 residents of Shenmu City. Data collection included questionnaires and anthropometric assessments to gather socio-demographic data and to identify cases of overweight, obesity, and central obesity. Multivariable logistic regression analysis was utilized to assess the association between various factors and these conditions. Results The observed prevalence rates for overweight, obesity, central obesity, and the combination of overweight/obesity with central obesity were 39.9%, 18.2%, 48.0%, 32.8%, and 22.8%, respectively. Notably, the incidence of these conditions was significantly higher in men compared to women. The prevalence of overweight and obesity initially increased and then decreased with age, whereas the prevalence of central obesity consistently rose. Furthermore, a higher educational level correlated with lower prevalence rates. Additionally, our analysis indicated that hypertension, dyslipidemia, and hyperuricemia are risk factors for these conditions. Conclusions The findings of this study offer crucial insights for formulating effective strategies to prevent and manage obesity in Shenmu City.


Introduction
Overweight, obesity, and central obesity are characterized as chronic metabolic disorders stemming from excessive total fat accumulation and/or localized fat increase with abnormal distribution.These conditions are commonly influenced by a synergy of genetic and environmental factors (Wei et al., 2022, Panuganti et al., 2022).In recent years, the prevalence of these conditions has escalated into a global public health concern due to economic advancement and improved living standards (Apovian et al., 2022, Pan et al., 2021, Hu et al., 2017).In 2016, it was reported that over 1.9 billion adults worldwide, aged 18 and older, were overweight, with more than 650 million classified as obese.The Report on Nutrition and Chronic Diseases in China (2020) indicates that 34.3 % of Chinese adults are overweight, and 16.4 % are obese, highlighting the significant public health challenge these conditions pose both globally and within China.
The impact of overweight, obesity, and central obesity extends beyond physical health, affecting mental well-being significantly.Research indicates a higher propensity for mental health issues, particularly anxiety and depression, among those affected by these conditions (Fulton et al., 2022).Moreover, overweight and obesity are not only chronic conditions in their own right but are also associated with a myriad of other chronic diseases including diabetes, stroke, coronary artery disease, hypertension, respiratory diseases, obstructive sleep apnea, osteoarthritis, and gallstones (Zhang et al., 2013, Powell-Wiley et al., 2021, Ibrahim and El-Sayed, 2021, Parra-Landazury et al., 2021).Furthermore, there is a well-documented link between obesity and an increased risk of various cancers, such as breast, colorectal, liver, among others (Larsson and Burgess, 2021, Maguire et al., 2021, Lee et al., 2019, Ma et al., 2013, Parida et al., 2019).Notably, studies have also identified obesity as a significant independent risk factor for adverse outcomes, including mortality, in cases of novel coronavirus pneumonia, with the severity of outcomes correlating with the degree of obesity (Simonnet et al., 2020, Zhou et al., 2021).
While the prevalence of overweight, obesity, and central obesity is widespread and affects all populations, significant geographical disparities exist.Despite numerous studies, there is a lack of large-scale data on the prevalence of these conditions in Shenmu City, Shaanxi Province.Thus, our study aims to assess the relationship between various risk factors and the prevalence of overweight, obesity, and central obesity among 4,565 adult residents of Shenmu City.The findings are expected to guide the development of health living guidelines for the local population and provide theoretical support for crafting relevant public health prevention policies.

Study participants
A multi-stage, stratified random sampling methodology was employed in Shenmu City, Shaanxi Province, China.Between August and December 2019, we selected adult participants from two communities (Linzhou and Yingbin Road) and four towns (Jinjie, Daliuta, Hejiachuan, Banbanbao) within Shenmu City for our survey.Initially, data from a total of 4,706 individuals were collected.After excluding 141 participants due to incomplete information, the final sample size comprised 4,565 individuals.This study received ethical approval from the Ethics Committee of Shenmu Hospital (Approval No. sm004), and informed consent was obtained from all participants.

Survey content
The survey consisted of two primary components: questionnaires and anthropometric measurements.The questionnaire captured various demographic and health-related data, including age, sex, place of residence, educational level, marital status, and medical history.Anthropometric measurements were conducted by trained medical personnel and encompassed height, weight, waist circumference (WC), and blood pressure.The Body Mass Index (BMI) was calculated using the standard formula: weight in kilograms divided by the square of height in meters.

Diagnostic criteria
(1) Overweight, obesity and central obesity were defined according to the Adult Weight Determination (WS/T 428-2013), 18.5 kg/ m 2 ≤ BMI < 24.0 kg/m 2 means normal weight, 24.0 kg/m 2 ≤ BMI < 28.0 kg/m 2 means overweight, BMI ≥ 28.0 kg/m 2 means obesity (Wang et al., 2014), and men waist circumference ≥ 90 cm and women waist circumference ≥ 85 cm means central obesity (Lim and Park, 2018).(2) Hypertension: Hypertension is defined as having a systolic blood pressure of 140 mmHg or higher and/or a diastolic blood pressure of 90 mmHg or higher.This definition applies regardless of whether the individual is taking antihypertensive medication (Yin et al., 2022).(3) Diabetes: Diabetes is defined as a fasting blood glucose level of 7.0 mmol/L or higher, or current use of hypoglycemic drugs or insulin (Jia et al., 2019).( 4) Dyslipidemia: Dyslipidemia is diagnosed when one or more of the following criteria are met: total cholesterol (TC) levels of 5.2 mmol/L or higher, triglycerides (TG) levels of 1.7 mmol/L or higher, and/or low levels of high-density lipoprotein cholesterol (HDL-C), specifically less than 1.0 mmol/L (Song et al., 2020).( 5) Hyperuricemia: Hyperuricemia is defined as having a fasting blood uric acid level exceeding 420 μmol/L in adults (Li et al., 2019)."

Statistical analyses
SPSS 25.0 software was used for descriptive statistics of all variables, t-test for continuous variables and chi-square test for categorical variables.Count data were expressed as the number of cases (%).χ 2 test and multivariable logistic regression were used to analyze the prevalence and epidemic characteristics of overweight, obesity and central obesity.A significance level of less than 0.05 (p < 0.05) was considered statistically significant.

Socio-demographic characteristics
A total of 4,565 adult residents of Shenmu City participated in this study, comprising 1,826 men and 2,739 women.The socio-demographic characteristics of the participants are detailed in Table 1.Men generally exhibited higher average height, weight, BMI, WC, systolic and diastolic blood pressure, and age compared to women, with these differences being statistically significant (p < 0.001).In terms of weight categories and central obesity, the incidence rates of overweight, obesity, and central obesity were significantly higher in men than in women.Agewise, the population of men over 60 was significantly larger than that of women in the same age bracket.Regarding education, women with a primary school education or less outnumbered their male counterparts, approximately doubling their number.Additionally, the prevalence of diabetes, dyslipidemia, and hyperuricemia was higher among men than women.However, no significant differences were observed in living areas, marital status, or the prevalence of hypertension between the genders.

Prevalence of overweight, obesity and central obesity
Table 2 presents the prevalence of overweight, obesity, and central obesity among adults in Shenmu, categorized by various demographic and health-related characteristics.These include sex, age, education level, residential areas (Urban, Northern township (industrial zone), Southern township (agricultural area)), marital status, and the presence of conditions such as hypertension, diabetes, dyslipidemia, and hyperuricemia.The result suggested that the overall prevalence of overweight, obesity and central obesity was 39.9 % (1820), 18.2 % (8 3 1) and 48.0 % (2192), respectively (Supplemental Fig. 1).In addition, it was worth noting that under different characteristics (Supplemental Fig. 2), there were significant differences between overweight and normal, obesity and normal and central obesity and non-central obesity (p < 0.05).The highest age of overweight and obesity in adults in Shenmu City was 40-49 years old, while the higher age of central obesity was over 50 years old.Similarly, Shenmu adults with primary school or below, southern township, married, and concurrent chronic diseases (including hypertension, diabetes, dyslipidemia, and hyperuricemia) have a higher prevalence.

Prevalence of overweight/obesity combined with central obesity
Table 4 presents the prevalence rates of overweight combined with central obesity and obesity combined with central obesity among adults in Shenmu, categorized by various characteristics such as sex, age, education level, living areas, marital status, hypertension, diabetes, dyslipidemia, and hyperuricemia.The study found that the prevalence of overweight combined with central obesity was 32.8 % (1,132 participants) and obesity combined with central obesity was 22.8 % (789 participants), as shown in Supplemental Fig. 1 Notably, there were significant differences in the prevalence of overweight combined with central obesity and obesity combined with central obesity across different demographic and health categories, as illustrated in Supplemental Fig. 3 (p < 0.05).The highest prevalence of overweight combined with central obesity was observed in participants aged 50-59 years, whereas the highest prevalence of obesity combined with central obesity was found in the 40-49 age group in Shenmu City.Furthermore, p-value was calculated by Pearson's χ2 test.the groups with a high prevalence of overweight or obesity combined with central obesity primarily included men, those with an education level of primary school or below, residents of the northern township, married individuals, and those with conditions like hypertension, diabetes, dyslipidemia, and hyperuricemia.

Discussion
Overweight, obesity, and central obesity are increasingly recognized as major global public health issues.It is projected that by 2030, approximately 1.35 billion and 573 million adults in China will be overweight and obese, respectively (Kelly et al., 2008).Currently, health problems and medical costs directly or indirectly associated with obesity are imposing a substantial economic burden on nations and societies.For instance, in 2020, the total cost of obesity in Italy was estimated at €13.34 billion, with cardiovascular diseases (CVD) being the most significant cost factor, followed by diabetes, cancer, and bariatric surgery (d'Errico et al., 2022).Recent research suggests that by 2030, medical expenses related to overweight/obesity in China could reach 418 billion yuan, accounting for about 21.5 % of the country's total medical expenditures (Wang et al., 2021b).This underscores the significant medical and economic impact of obesity on individuals, countries, and societies.
This study analyzed the prevalence of overweight, obesity, central obesity, and their combinations among adult residents of Shenmu, Shaanxi Province.The findings revealed prevalence rates of 39.9 % for overweight, 18.2 % for obesity, 48 % for central obesity, 32.8 % for overweight combined with central obesity, and 22.8 % for obesity combined with central obesity.Notably, the prevalence of central obesity was higher than that of other categories, suggesting that, compared to systemic obesity, central obesity is more prevalent among adults in Shenmu City.Recent studies have linked abdominal obesity with insulin resistance and a heightened risk of metabolic syndrome and cardiovascular diseases, more so than overall obesity (Goh and Hart, 2018).Other research indicates that central obesity is a more accurate predictor of cardiovascular disease risk than systemic obesity and is considered a significant risk factor for cardiovascular and metabolic diseases (Piché et al., 2018).Specifically, a study in Shaanxi, China, found that normal weight individuals with central obesity had an increased risk of cardiovascular diseases, such as hypertension and dyslipidemia, regardless of sex (Feng et al., 2021).Therefore, central obesity warrants special attention from relevant authorities.
The prevalence and risk factors of overweight, obesity, and central obesity among adult residents of Shenmu City appear to be influenced by various factors.Regarding gender, the prevalence of overweight, obesity, and central obesity is generally higher in men than in women.This finding aligns with the research by Junjie Hua et al. (Hua et al., 2020, Wang et al., 2021a), The prevalence and risk factors of overweight, obesity, and central obesity among adult residents of Shenmu City appear to be influenced by various factors.Regarding gender, the prevalence of overweight, obesity, and central obesity is generally higher in men than in women.This finding aligns with the research by Junjie Hua et al. (Liu et al., 2021) and may be linked to the increased family responsibilities often associated with married life.
In addition to the aforementioned factors, hypertension, diabetes, dyslipidemia, and hyperuricemia are also intricately linked to overweight, obesity, and central obesity.Studies indicate that Shenmu residents with these conditions are more susceptible to overweight, obesity, central obesity, and a combination of overweight/obesity with central obesity.These findings align with related research (Movahed et al., 2016, Bragg et al., 2018, Lee et al., 2022, Yu et al., 2016), underscoring the importance of managing hypertension, diabetes, dyslipidemia, and hyperuricemia in the prevention of overweight, obesity, and central obesity.However, as this study is cross-sectional in nature, the causal relationships between these health conditions and various forms of obesity warrant further investigation through cohort studies.
In conclusion, the prevalence of overweight, obesity, and central obesity among adult residents in Shenmu City is high, with multivariable influencing factors, including gender, age, education level, living areas, economic status, marital status, and chronic metabolic diseases.Fortunately, these conditions are preventable and controllable.This necessitates awareness from relevant authorities, who should engage in health promotion activities aligned with the 'Healthy China 2030′ initiative, develop effective prevention and control strategies, and work towards improving the health of the population at large.

Conclusions
Recent research indicates that adult residents in Shenmu City exhibit high prevalence rates of overweight, obesity, central obesity, and combinations of overweight or obesity with central obesity.Particularly noteworthy is the prevalence of central obesity, which significantly increases the risk of cardiovascular diseases and chronic metabolic disorders among the city's population.This study offers valuable insights and serves as a reference for developing effective intervention measures and prevention strategies to combat obesity.

Ethics statement
This study was approved by the Ethics Committee of Shenmu Hospital (NO.sm004), and all subjects signed informed consent.

Table 1
Socio-demographic characteristics of the studied adults in Shenmu city, Shaanxi province, 2019.
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Table 2
Distribution of overweight, obesity and central obesity of the studied adults in Shenmu city, Shaanxi province, 2019.

Table 3
Association between the factors and overweight, obesity and central obesity of the studied adults by multivariate logistic regression analysis in Shenmu city, Shaanxi province, 2019.
p-value was calculated by logistic regression analysis with adjustments for age and gender.Bold values indicated that the p-value was statistically significant.

Table 4
Distribution of overweight/obesity combined with central obesity of the studied adults in Shenmu city, Shaanxi province, 2019.
p-value was calculated by Pearson's χ2 test.