hile infectious diseases continue to plague sub-Saharan Africa, the rapid increase in noncommunicable diseases (NCDs) is exacerbating an already distressing situation. Faced by impoverished health care systems and poor infrastructure, a rising trend of NCDs in Africa is making the battle against the ever present infectious diseases even more difficult. Cardiovascular disease is currently the number one killer in developing countries, claiming as many lives as HIV, TB and malaria combined. [1][2][3] With a 7% attribution to the global burden of disease, hypertension is indeed the single most substantial cause of disability and mortality worldwide. [4][5][6] Accountable for about 50% of deaths due to heart disease, kidney failure and stroke in 2013, hypertension remain a significant threat to global health and development. [7][8][9] Despite having a high asymptomatic potential, easy diagnostic modality, and a clear management strategy, the rates of hypertension awareness, treatment and control is very low especially in developing nations. 10 Tanzania like other third world countries is witnessing an upsurge of NCDs with hypertension among the leading etiologies. This community-based survey conducted in Kinondoni district, Dar es Salaam, aimed to determine the prevalence, awareness, control and associated factors for high blood pressure in the targeted urban population. the screening advert through the media were recruited and screened. Socio-demographic parameters were gathered through interviews utilizing a structured questionnaire. We grouped age into 4 categories; children: <18 years, young adults: 18-39 years, middle age 40-54 years and elderly: ?55 years. 11 Physical activity was assessed using the Physical Activity Vital Sign (PAVS) scale 12 ; with scores of 0 minutes/week denoting inactivity, 1 -<150 minutes/week signifying underactivity and ?150 minutes/week indicating physical activeness. Weight and Height were measured using the standard measuring scales and BMI for those aged 20 years and above was calculated by a ratio of weight (in kilograms) to height (in meters) squared. For those under 20 years, a CDC BMI calculator for children and teens 13 was utilized. We defined underweight as BMI<18.5 kg/m 2 , normal: BMI 18.5-24.9 kg/m 2 , overweight: BMI 25-29.9 kg/m 2 and obese: BMI ?30 kg/m 2 . 14 Individuals who smoked at least 1 cigarette in the past 6 months were regarded as current smokers, those who last smoked over 6 months or self-reported quitting smoking were considered past smokers and those who never smoked but currently live with a smoker were regarded as passive smokers. Alcohol drinking was defined as at least a once consumption every week. Alcohol dependence was assessed by the CAGE questionnaire 15 , where a total score of 2 or greater was used to define alcohol dependence. Blood pressure (BP) was measured by digital BP machines where a systolic blood pressure (SBP) <120 mmHg and a diastolic blood pressure (DBP) <80 mmHg was used to define normotension/optimal BP. Pre-hypertension was defined by SBP of 120-139 mmHg or DBP of 80-89 mmHg, while SBP ?140 mmHg or DBP ?90 mmHg indicated hypertension. 16 A hypertensive subset with SBP ?180 mmHg or DBP ? 110 mmHg was regarded as hypertensive crisis. 17 Awareness of hypertension was defined as a self-report of any prior diagnosis of hypertension in a health facility and/or use of antihypertensives. Controlled hypertension/BP was defined as awareness of hypertension associated with a SBP <140mmHg and DBP <90mmHg. All interviewers and medical personnel involved in the screening were familiar with the study aims and methods.

All statistical analyses were performed by STATA v11.0 software. Summaries of continuous variables are presented as means (± SD) and categorical variables are presented as frequencies (percentages). Categorical and continuous variables were compared using the Pearson Chi square tests and Student's T-test respectively. Bivariate analyses were performed to assess for factors associated with high blood pressure. Significant variables (p<0.05) were then entered in a multivariate logistic regression model to control for confounders. Odd ratios with 95% confidence intervals and p-values are reported. Statistical significance was set at p<0.05 and all tests were two tailed. The mean BMI of participants was 27.8 ± 7.1. Overall, 97 (5.4%) were underweight, 544 (30.3%) had normal BMI, and 1155 (64.3%) were overweight or obese; Table 2. Age ?40 and female sex displayed a higher likelihood for being overweight and/or obese, (OR 4.0, 95% CI 3.2-5.0, p<0.001 and OR 2.3, 95% CI 1.8-2.8, p<0.001 respectively).

Of the 1796 persons who responded to the questions regarding history of chronic disease, 688 (38.3%) had a history of at least one chronic illness. Cardiovascular related diseases were reported by 612 (88.9%) of those with a positive history of chronic illness, 559 (91.3%) of whom had hypertension awareness.

The prevalence of hypertension in this study was 63.3% (1137/1796) and 49.2% (559/1137) of these were aware of their hypertensive status. The mean SBP and DBP of persons aware of their hypertensive status was 166.0 ± 29. 8

Nearly two-thirds of individuals in this recent urban community-based screening had high blood pressure. In contrast to previous studies, these findings are substantially high. In a systematic review of hypertension studies in Africa by Addo 18 et al, there was a wide variation in hypertension prevalence ranging from 9.3% 19 in Ethiopia to 48.1% 20 in Mozambique. Our findings nevertheless are in unison with another population-based Tanzanian study which found a prevalence of 70% 21 , this study however involved persons aged above 70 years.

Correlates of high blood pressure included age ?40, male sex and BMI ?25 which were associated with up-to 5-fold increased chance of being hypertensive. These factors and others including physical inactivity are well established risk factors that have been consistently demonstrated in several studies. 22,23 The rates of hypertension were nearly similar to the rates of excess body weight in this study. This potentially implied that overweight/obesity was the strongest modifiable factor associated with hypertension. Physical inactivity was not a significant factor for hypertension in this present study, it should be noted however that the population we screened was predominantly inactive. Moreover, the observation that females were more likely to be inactive than males was reciprocated in the BMI measurement in the sense that females displayed higher likelihood for excess body weight compared to males. The overall rates of obesity in this present study were almost twice the rates found by Shayo 24 et al in the same setting in 2010. In unison to Shayo et al study, we also found higher rates of obesity among females. We were intrigued by the observation that although females were significantly obese than males, hypertension rates were higher in males compared to females. Androgen mediated abnormalities in pressure natriuresis is currently the plausible theory explaining the differences in hypertension rates between sexes. 25 One in every two persons with high blood pressure in this study was unaware of their hypertensive status. Reported rates of hypertension awareness in Africa ranges from 12.3% among Nairobi slum dwellers to 81% in urban Tunisia. 26,27 Remarkably, one out of every five persons who were unaware of their hypertensive status had BP elevated to crisis levels. It is well known that such high BP is critical and warrant immediate evaluation as can result to multiple organ failure including blindness, kidney failure, heart failure and stroke. 17 One third of newly diagnosed hypertensives had echocardiographic changes consistent with hypertension (i.e. left ventricular hypertrophy). This finding reflects the high asymptomatic potential of hypertension and suggests that regular BP measurement is important. Hypertension control rates are uniformly low amongst studies and according to a systematic review by Kayima et al, Tanzanian populations whether urban or rural had the lowest control rates of <7%. 3 In contrast to these findings, our control rates were over twice as much and even so should be regarded as low.

This study has a number of strengths including; (i) we recruited over 1800 persons, a good number suitable for subgroup analyses, (ii) the use of standard tools which allow for comparability among studies, and (iii) we performed ECHO on a subset of individuals aware of their hypertension status and those newly diagnosed to assess for cardiovascular changes associated with hypertension. Our study had some few limitations including; (i) the recruitment process and measurements (weight, height and BP) could have potentially introduced selection bias and non-differential bias respectively, and (ii) our hypertension rates could be somewhat overestimated as we relied on a single occasion BP measurement to make the diagnosis. Future studies in this area should thoroughly assess dietary habits and salt intake and its association with excess body weight and hypertension.

In conclusion, our findings suggest that excess body weight is a single modifiable risk factor strongly associated with high blood pressure. Moreover, majority of persons with hypertension are undetected and thus unaware of their hypertension status. In view of this,