Association between obesity and high blood pressure: Reporting bias related to gender and age

Abstract

OBJECTIVE: To examine the validity of self-reported information on obesity and high blood pressure (HBP) in relation to gender and age, and to explore the impacts of their misclassi®cation on the association between obesity and HBP. DESIGN: Community based cross-sectional study. SUBJECTS: 1791 adult subjects living in Humboldt, Saskatchewan, Canada. MEASUREMENTS: Objectively measured HBP was positive if systolic blood pressure (BP) was !140 mm Hg, diastolic BP was !90 mm Hg or the subject was currently using antihypertensive medication. Self-reported HBP was positive if the subjects gave an af®rmative response to the question:`Has a doctor ever said you had high blood pressure?' Body mass index (BMI) was calculated as weight (kg)aheight (m) 2 . Obesity was de®ned as a BMI b 27 kgam 2 . Measured obesity and reported obesity were based on measured and self-reported information on height and weight, respectively. RESULTS: The sensitivity of self-reported HBP was low, and was lower for men than for women, and for younger subjects than for older subjects. The speci®city was similar for both genders. Obese individuals had higher sensitivity and lower speci®city than non-obese individuals. The differential misclassi®cation of self-reported HBP caused a bias away from the null when the relative risk for HBP in relation to obesity was estimated. CONCLUSIONS: As a result of the gender-and age-related misclassi®cation of self-reported HBP, the modi®cation role of gender and age on the association between obesity and HBP could be altered. The bias caused by self-reported obesity was relatively small and was either toward or away from the null.

Association between genetic variation of the insulin receptor gene and essential hypertension in the Korean population

“…The reason why the association was not confirmed in obese hypertensives may be explained by the fact that this effect was masked in this group by the influence of high BMI. In other words, the association between Nsi\ RFLP of INSR gene and essential hypertension seems to be diluted by the presence of obesity, since obesity itself is known to be caused by various genetic and Schrader et al, 1996 Present study environmental factors, and strongly associated with insulin resistance and essential hypertension (Chen et al, 1998;Kroke et al, 1998;Wannamethee et al, 1998). Therefore, these results strongly suggest that the A/s/l RFLP of INSR gene is associated with essential hypertension, independently of obesity.…”

Gender-related differences in the association between socioeconomic status and self-reported diabetes

“…Such a reporting bias, however, is small and non-differential to disease outcomes, and has little impact on association estimation. 29 In summary, we found that Canadian women ജ40 years of age of low SES had a higher prevalence of type 2 diabetes, independent of age, area of residence, obesity, and physical inactivity. This relationship was weaker in men and accounted for the confounding factors stated above.…”

Stronger associations of obesity with prehypertension and hypertension in young women than in young men

“…This is the first study demonstrating significant sex-specific difference in the degree of association between obesity and blood pressure status by using statistical analysis. There is a controversy regarding the effect of sex on the association between obesity and hypertension: the association has been shown to be stronger in women than in men by a Canadian group [6], not to be different between men and women by Japanese and Croatian groups [7,8] and to be stronger in men than in women by an Indian group [9]. Using white and black American individual, increased OR for prehypertension associated with obesity has been shown to be higher in women than in men, but this sex difference was small in Hispanic Americans [17].…”

“…In the present study, using logistic regression analysis and analysis of AUC, the associations of obesity with prehypertension and hypertension were demonstrated to be significantly stronger in women than in men. Interestingly, the sex difference in the association between obesity and hypertension has been shown to become weaker in older age [6], and this suggests involvement of a sex hormone such as estrogen in the sex difference. In the present study, only young people (20-39 years) were enrolled, because menopausal status possibly confounds the relationship between adiposity and blood pressure.…”

“…Sex-specific differences in prevalence of hypertension and obesity are known: prevalence of hypertension and obesity in women before menopause are lower than those in men of the same ages [2,3]. Although a potent association between obesity and hypertension has been shown [4,5], there is limited information on effect of sex on the association between obesity and hypertension, and findings of previous studies are controversial: the association was stronger in women than in men in one [6], comparable between men and women in some [7,8] and stronger in men than in women in another [9], although statistical analysis for comparison between men and women was not performed in those studies.…”