| BackgroundHypertension has the main feature with increased arterial blood pressure throughout the systemic circulation,often accompanied by structural or functional damage to the kidney,brain and heart.Hypertension is a crucial contributor to the global burden of health and a capital public health issue in China.Globally,1.28 billion adults had high blood pressure in 2019,and this number is expected to reach 1.56 billion in 2025,accounting for 29.2%of the worldwide population.According to the 2020 Report on Cardiovascular Health and Diseases in China,the prevalence of hypertension was 27.9%among residents aged 18 and above,and more than 50%among people aged 65 and above.Although the prevalence of hypertension in China is on the rise,its awareness rate,treatment rate and control rate are still at a relatively low-level.Considering the severity of its harm and the complexity of its control,it is imperative to identify and control its causes early and to take scientific and targeted strategies and measures to prevent its occurrence.Epidemiological studies have shown that overweight and obesity are crucial risk factors for hypertension.The distribution of body fat in the Chinese people has specific characteristics,which is manifested as a mild degree of obesity,while the distribution of body fat tends to gather in the abdominal cavity,resulting in abdominal obesity easily.In the past two decades,with the increase of the overall obesity rate in the Chinese population,the prevalence of abdominal obesity has also increased significantly.Waist circumference measurement is widely used because it is a simple,dependable,inexpensive and noninvasive way to assess abdominal fat.Studies have shown a higher correlation between abdominal fat accumulation and cardiovascular disease.Additionally,waist circumference is of great value in predicting the risk of cardiovascular disease.Waist circumference varies dynamically over the life course.Previous studies on waist circumference and hypertension at home and abroad were mostly cross-sectional studies or cohort studies based on the limited number of measurements.Absolute or relative changes in waist circumference were used to reflect changes in waist circumference during follow-up,while the impact of the dynamic development trajectory of waist circumference on the risk of hypertension was ignored.Waist circumference trajectory can reflect the long-term process of waist circumference development with age.However,few studies have explored the dynamic trajectory of waist circumference in adulthood among the Chinese population and its association with incident hypertension.Objectives1.To explore the waist circumference development trajectory and gender-specific waist circumference development trajectory in adulthood(18-60 years old),and analyze its association with incident hypertension.2.To explore the waist circumference development trajectory and gender-specific waist circumference development trajectory in early adulthood(18-40 years old)and late adulthood(40-60 years old),and analyze its association with incident hypertension.MethodsThis study adopted data derived from the Chinese Health and Nutrition Surveys from 1993 to 2015,including participants without high blood pressure at baseline,who participated in at least 3 surveys and were in adulthood(18-60 years old)during the follow-up.Group-based trajectory Modeling(GBTM)was used to analyze the dynamic changes in waist circumference with age,and identify potential clusters with similar trajectories.GBTM traversed 2-5 groups,each group of tracks traversed 1-3 polynomial equations,and the optimal trajectory model was selected based on the Bayesian information criterion and model evaluation criterion.ANOVA analysis and Pearson’s χ2 test were used to compare the differences in basic characteristics of people with distinct waist circumference trajectories.Multinomial logistic regression model was used to analyze the influence of sociodemographic factors,lifestyle factors and dietary factors on the development of waist circumference trajectory.Cox proportional risk regression model was used to explore the association of different waist circumference trajectories with incident hypertension,adjusting for confounding factors such as baseline age,sex,education level,smoking,alcohol consumption,body mass index,and dietary status,etc.Among males and females,waist circumference trajectory analyses were performed again and Cox proportional risk regression model was used to analyze the relationship between gender-specific waist circumference trajectories and incident hypertension.Statistical analyses were conducted using Stata 16.0(Stata Corporation,College Station,TX,USA)and R 4.1.2 software,and two-tailed P<0.05 was considered statistically significant(α=0.05).Results1.Association of the waist circumference trajectories in adulthood with incident hypertensionThere were four different waist circumference trajectories among the participants:the lowincreasing group(23.84%),the moderate-increasing group(43.66%),the high-increasing group(25.69%)and the sharp-increasing group(6.18%).With the low-increasing group as the reference,the hazard ratios(HR)and 95%confidence interval(CI)for the moderate-increasing group,the high-increasing group,and the sharp-increasing group were 1.52(1.25-1.87),2.32(1.82-2.96)and 3.15(2.21-4.51),respectively,after adjusting the baseline age,sex,education level,BMI,smoking status,alcohol consumption status and dietary status.The results of the sex stratification analysis showed that among both the males and females,the risks for hypertension were significantly higher in other steep increasing groups compared with the participants in the low-increasing group.There were four gender-specific waist circumference trajectories among the males and the females during adulthood.In the males,after adjusting the covariates,the hypertension HR(95%CI)for the moderate-increasing group,the high-increasing group,and the sharp-increasing group were 1.63(1.26-2.11),2.61(1.903.60)and 3.85(2.36-6.29),respectively,with the low-increasing group as the reference.In the females,after adjusting the covariates,the hypertension HR(95%CI)for the moderateincreasing group,the high-increasing group,and the sharp-increasing group were 1.71(1.162.54),2.05(1.33-3.16),and 2.43(1.33-4.44),respectively,with the low-increasing group as the reference.2.Association of the waist circumference trajectories in early adulthood with incident hypertensionThere were three different waist circumference trajectories among the participants in early adulthood:the low-increasing group(48.28%);the moderate-increasing group(40.84%)and the high-increasing group(10.88%).Compared with the low-increasing group,the HR(95%CI)for the moderate-increasing group and the high-increasing group were 1.41(1.05-1.96)and 1.75(1.16-2.91),respectively.The results of the sex stratification analysis showed that in the males,the risks for hypertension in other steep increasing groups were significantly higher compared with the participants in the low-increasing group.In females,there was no statistically significant association between waist circumference trajectories and incident hypertension.There were three gender-specific waist circumference trajectories among the males and females during early adulthood.In the males,compared with the low-increasing group,the hypertension HR(95%CI)for the moderate-increasing group and the high-increasing group were 1.72(1.11-2.67)and 2.21(1.10-4.47),respectively.In the females,there was no significant association between the waist circumference trajectories and incident hypertension.3.Association of the waist circumference trajectories in late adulthood with incident hypertensionThere were four distinct development trajectories of waist circumference in late adulthood:the low-stable group(14.48%),the low-increasing group(41.95%),the moderate-increasing group(34.47%)and the high-increasing group(9.10%).Compared with the low-stable group,the hypertension HR(95%CI)for the low-increasing group,the moderate-increasing group,and the high-increasing group were 1.53(1.16-2.02),2.28(1.70-3.06)and 2.84(1.95-4.14),respectively.The results of the sex stratification analysis showed that among both the males and females,the risks for hypertension were significantly higher in other steep increasing trajectory groups compared with those in the low-stable group.There were four gender-specific waist circumference trajectories among the males and females during late adulthood.In the males,compared with the low-stable group,the hypertension HR(95%CI)for the lowincreasing group,the moderate-increasing group,and the high-increasing group were 1.30(0.90-1.87),2.29(1.56-3.37),and 2.80(1.73-4.52),respectively.In the females,compared with the low-stable group,the hypertension HR(95%CI)for the low-increasing group,the moderate-increasing group,and the high-increasing group were 1.90(1.24-2.90),2.26(1.423.60)and 2.83(1.51-5.29),respectively.Conclusions1.There were distinct waist circumference trajectories in adults.There were four waist circumference trajectories in the whole adulthood:low-increasing trajectory,moderateincreasing trajectory,high-increasing trajectory and sharp-increasing trajectory;there were three waist circumference trajectories in the early adulthood:low-increasing trajectory,moderate-increasing trajectory and high-increasing trajectory;and there were four waist circumference trajectories in the late adulthood:low-stable trajectory,low-increasing trajectory,moderate-increasing trajectory and high-increasing trajectory.2.Compared with the low-increasing(or low-stable)trajectory,the risks for incident hypertension in other steep increasing trajectories were significantly higher.It suggests that attention should be paid not only to the influence of body fat content on incident hypertension but also to the influence of body fat distribution and growth rate on incident hypertension.3.Gender-specific waist circumference trajectories during adulthood and its different period(the early and the late)were closely associated with incident hypertension.Even if the trajectory was maintained below the threshold of abdominal obesity,it could still increase the risk for hypertension.It indicates the epidemiological significance of early waist circumference health management in preventing hypertension. |
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