The Community-based Intervention Research On The Relationship Between OC And Hypertension Among Chinese Rural Women

The association between oral contraceptives(OC)and cardiovascular diseases was reported since the late 1950s when OC was on market.Since then,measures of lowering the dosage and improve the preparations had been carried out to reducing the side effects of OC. However,reasearches still found that it can increase the blood pressure and risk of cardiovascular diseases.Hence,OC as an important risk factor of hypertension has been listed to Hypertension Guidline by WHO. In China,the association between OC and hypertension has been reported since 1990s.However,it has not been paid enough attention. The latest Chinese Guidline of Hypertension donot even mention the effect of OC on blood pressure.Our research aims to make clear about the association between OC and hypertension so as to provide a scientific evidence for carring out effective intervention measures on women and decrease the side effect of OC.Taicang County and Rudong County of Jiangsu Province have the longest history of OC use and the prevalence of OC use is highest in China.About 12.0%of child-bearing aged women are current OC users, and nearly 50%have a history of OC use.Shaxi Town of Taicang County and Matang Town of Rudong County were chosen as research field.The aims of this study are to make clear about the association of OC and hypertension in Chinese women,carry out intervention measures to reduce the risk of hypertension and provide an evidence for further intervention of hypertension among women. PartⅠThe cross-sectional study on the association between OC and hypertensionReseaches found that low dosage of OC can still raise the blood pressure and risk of cardiovascular diseases.Hence,OC as an important risk factor of hypertension has been listed to Hypertension Guidline by WHO.However,the side effect of OC on hypertension has not brought enough consideration and there is little relative study.In a cross-sectional study,we studied women from Taicang and Rudong County and divided them into three groups according to OC use:never users of OC,past users of OC,and current users of OC.The blood pressure and risk of hypertension among the three groups were compared to analyze the relationship between OC and hypertension.The main results are as following:1.The mean blood pressure was higher in current users of OC(mean systolic blood pressure(MSBP),120.48±14.20 mmHg;mean dystolic blood pressure(MDBP),77.93±8.68 mmHg)than in never users of OC (MSBP,115.93±12.33 mmHg;MDBP,75.8±8.99 mmHg)and past users of OC(MSBP,118.02±14.21 mmHg;MDBP,74.99±8.02 mmHg) (P＜.0001).The difference of blood pressure between never users of OC and past users of OC was not significant.2.The prevalence rate of hypertension varied among never users of OC,past users of OC and current users of OC,current users was highest(12.08%),then was past users(9.00%),and never users(6.84%) was lowest. 3.The prevalence rate of hypertension increased with the duration of oral contraceptive use,from 6.06%,9.37%,13.69%to 17.17%with the duration of oral contraceptive use from 0 year,<5year,5-10year to >10year,respectively.4.In a logistic regression model,we found that oral contraceptive use was associated with hypertension,the risk of hypertension was 1.51 (95%CI,1.23-1.85)times in past users of OC than in never users of OC,and the risk of hypertension was 2.21(95%CI,1.76-2.77)times in current users of OC than in never users of OC.PartⅡEffects of Community-based Intervention on hypertension among womenOC is an important risk factor of hypertension.Moreover, hypertension is the most important risk factor of cardiovascular disease. We carried out comprehensive intervention among 10 313 women aged 23-70 in Rudong and Taicang.The measures include:health examination before OC use and only eligible women were allowed to use it; monitoring of blood pressure during the period of using OC;guidance of treatment;health education and promotion.Aims of this study are to reduce the risk of hypertension in these areas and provide an evidence for further intervention of hypertension among women where OC use is popular.Main results are as following:1.Control rate of hypertension at baseline and follow-upControl rate of hypertension(HCR)increased significantly from 2.26% to 26.21%after intervention(P＜0.0001).In Rudong County,the HCR increased from 3.31%to 24.04%,and in Taicang from 1.56%to 27.13%. The increment in Taicang were higher than in Rudong(P=0.0302).There were also significant increment in HCR for both child-bearing aged women and the older,but the increment between them had no significant difference.2.Blood pressure at baseline and follow-upAfter intervention,both MSBP and MDBP of hypertensive declined to normal range significantly(P＜0.0001).MSBP declined from (142.38±12.84)mmHg to(139.05±19.24)mmHg,MDBP declined from (90.87±7.25)mmHg to(83.67±9.92)mmHg.The decrement of MSBP was more significant in child-bearing aged women than that of no child-bearing aged women(P＜0.0001),while the decrement of MDBP more significant in the older(P=0.0068).The decrement of MSBP and MDBP of child-bearing aged women were 5.19 mmHg and 6.45 mmHg; the decrement of MSBP of no child-bearing aged women was not significant,and the decrement of MDBP was 8.34 mmHg.4.The classification of hypertension at baseline and follow-up Hypertensive patients with BP at normal range,mild,intermediate and severe occupied 2.19%,82.35%,13.26%and 2.19%,respectively at baseline.After intervention they were 51.25%,32.90%,12.56%and 3.29%,respectively.The improvement was significant(P＜0.0001).5.The prevalence of current users of OC at baseline and follow-up The prevalence of current users of oral contraceptives among child-bearing aged women with hypertension decreased significantly from 23.90%to 18.05%(P=0.0143) 6.The effect of intervention on the influence factors of hypertension Comparing different influence factors to hypertension at baseline and follow-up,we found that the risk of hypertension among current users of OC decreased significantly,and the intervention effects were better in Taicang county,child-bearing aged women,none-agricultural subjects and no family history of hypertension,respectively.Among child-bearing aged women,the effects were better in Taicang county and no family history of hypertension subjects;among no child-bearing aged women,the effects were better in no family history of hypertension subjects.In Rudong County,the effects were better in none-agricultural subjects,BMI＜24Kg/m~2 subjects and no family history of hypertension subjects;in Taicang County,the effects were better in none-agricultural subjects,chil-bearing aged subjects and no family history of hypertension subjects.Conclusion:1.OC is an important risk factor of hypertension.Compared to never users of OC,the risk of hypertension was 1.51(95%CI,1.23-1.85)for ever users and 2.21(95%CI,1.76-2.77)for current users.2.The risk of hypertension increased with the period the using OC.3.The beneficial effect of this comprehensive intervention which included the intervention on OC use was confirmed in this study.The control rate of hypertension increased significantly,the mean blood pressure decreased to normal level and the risk of hypertension declined.4.The child-bearing aged women,people who were not farmers,and people without family history of hypertension had a better intervention effect than people who were older,farmers and with family history of hypertension,respectively. Suggestions:List OC as an important risk factor in《Chinese Guidline of Prevention and Treatment of Hypertension》to make clinical practioners be aware of the side effect of OC;Carry out specialized hypertension intervention measures among child-bearing aged women;Family planning workers should be trained about the indications and contraindications of OC,side effects of OC;Child-bearing aged women should learn about the side efffects of OC before taking it,and have blood pressure taken regually during the period of using OC.