Dietary intake and the dynamics of stress , hypertension and obesity in a peri-urban community in Accra

Husein Mohammed, Shibani Ghosh, Fred Vuvor, Seth Mensah-Armah, Matilda SteinerAsiedu Department of Nutrition and Food Science, University of Ghana, Accra, Ghana Nevin Scrimshaw International Nutrition Foundation, Boston, USA Friedman School of Nutrition Science and Policy, Tufts University, Boston, USA School of Dietetics and Human Nutrition, McGill University, Canada Department of Food and Nutrition, Iowa State University, Iowa, USA.


INTRODUCTION
Hypertension is defined as having blood pressure greater than or equal to 140/90 mm Hg, or currently undergoing anti-hypertensive treatment. 1Hypertension is now being widely reported in Africa and is the most common cause of cardiovascular disease on the continent. 2It is also a major factor in the high mortality of adults in sub-Saharan Africa. 3In Ghana, hypertensive renal disease is a common complication in both Kumasi and Accra. 4etary intake has been associated with increase or decrease prevalence of hypertension.Excessive consumption of sodium in diet, alcohol, saturated fatty acids and cholesterol have been associated with increased risk of developing hypertension, while high intake of potassium, calcium, magnesium and polyunsaturated fatty ac-ids rich foods have been associated with decrease in occurrence of hypertension and its related cardiovascular diseases in populations. 5lliams 6 noted that the adaptive response to stress prepares individuals for fight or flight mechanism, but stress due to current lifestyles negatively impacts the response.This may result in reduced immune function and the emergence of diseases such as coronary heart disease, cancer, diabetes and hypertension.Stress also initiates the release of aldosterone, a corticosteroid that causes renal sodium retention, and vasopressin (antidiuretic hormone), which stimulates renal tubular water resorption thereby increasing blood volume and subsequently blood pressure. 5hronic mental stress or high basal levels of stress hormones contribute to the development of peripheral disease 7 and clinical anxiety. 8However, in coping with mental stress, Fernstrom 9 showed the importance of dietary essential amino acids.Recent studies have indicated that the essential amino acid L-lysine (Lys) reduces anxiety 10 and normalizes stress-induced hormonal responses in healthy subjects with relatively high perceived anxiety. 11Animal foods on an average contain 85mg lysine per gram protein.In contrast to animal foods, cereals are not a good source of lysine and contain only 30 mg/g protein. 12e relationship between hypertension and dietary intake has been extensively documented but that of hypertension and stress is a vicious cycle.Understanding of the causal path of the cycle is a key to managing hypertension.It is against this background that this study was postulated.

Research design, setting and population
This study is part of the baseline study of a supplementation trial conducted in two peri-urban communities in Accra.These communities were chosen because they have nucleated settlement, were densely populated, with mostly low socio-economic status and had poor social amenities, making them highly prone to stress and poor nutrition and hence hypertension.

Sampling and Ethics
Using a point estimate of 0.5, allowable error of 7%, at 95% confidence interval, a sample size of 194 was obtained.To ensure participation of the entire community, a house-to-house recruitment was done, and households who qualified and agreed to participate in the study were recruited and coded.Study participants were then randomly selected from those recruited.The study was thoroughly explained to the participants and those who signed the consent forms were selected for the study.A total of 90 households consisting of a man and woman (totalling 180 subjects), between the ages of 18 to 45 years, who have lived in the community for at least one year were recruited into the study.Selected subjects were also free from any physical and mental disabilities.The study protocol was reviewed and approved by Internal Review Board of the University of Ghana.Reconnaissance meetings were held with the chiefs and leaders of the communities and appropriate permission was provided before the commencement of the project.

Data collection
Socio-demographic information was collected using standardized questionnaire.Anthropometric measure-ments (height, weight and skinfold measurements), and 3-day repeated 24-hours dietary recall (two week days and one weekend to help get the subjects typical day's meal) were taken with the help of food models.The foods were converted into nutrients using the Ghana food composition table and USDA food composition table. 13Blood pressure was taken using sphygmomanometer at rest using standard procedure. 14Chronic anxiety was assessed using a local language translated and back translated (standardized) version of trait-state inventory (t-STAI) questionnaire.An inventory composed of 20 items for assessing chronic anxiety. 15Each item has a score of 1 to 4, and the higher the cumulated score of a subject the higher the anxiety.A time difference of at least one week was allowed between obtaining t-STAI responses and blood pressure data collection. 10

Ethical Approval
The Noguchi Memorial Institute for Medical Research Institutional Review Board approved the study.Consent forms were signed by all individuals who agreed to participate in the study after an explanation of the project in their local language.

Data Analysis
Data was entered in MS Access and data analysis was done using MS Excel spread sheet and SPSS.USDA data base 13 was used in addition to the Ghanaian food composition tables, for detailed nutrient analysis including fatty acid breakdown and amino acid profile of the diet.Frequency distribution, chi-spare analysis, and linear regression analysis was used in data analysis.ANOVA and ANCOVA was used to control confounders during analysis.

RESULTS
Most of the respondents were between 18 to 38 years (71%).The mean age (standard deviation) for the population was 33(7) years whiles, that of males was 33(8) years and females was 32(7) years.Majority of the subjects were in the low socioeconomic class.Majority of the male subjects were drivers (15.6%) and masons (16.7%); whiles most of the females were traders (60%).
In general, there was inadequate intake of calcium (27.20% of RDA) and potassium (45.17% of RDA), and excess intake of sodium (197.88% of RDA), especially in male subjects (219.68% of RDA).Among all subjects, mean dietary intake of calories, (less than 65% of Average Energy Requirement or AER), were below their recommended requirement.Additionally, male intake of fibre (58.3% of RDA) and female intake of iron (51.5% of RDA) were low.About 28.4% of the participants were hypertensive and a further 36.4% of them were pre-hypertensive (table 1).Most of the hypertensive subjects (98%) did not know their condition and hence were not under any form of treatment.Hypertension was higher among males (32.2%) than in females (24.4%).In total, hypertensive and pre-hypertensive subjects combined, make up 70% of males and 59.3% of female subjects in the study community.Overweight/obesity was also high, with 21.3% of the population being overweight and 14% obese.Obesity was more endemic in females (26.1%), with a 53.4% combined prevalence of overweight and obesity (Figure 1).

Table 1 Distribution of malnutrition, hypertension and stress in study community
Hypertensive subjects had significantly higher mean sodium intake than normal subjects (p=.026).They recorded over 200% higher intake of sodium than the recommended dietary allowance.Male hypertensive subjects also had higher sodium intake than their normal counterparts (p=.013), this was however not seen in female subjects (p=.997).Body mass index (BMI) was much higher in hypertensive and pre-hypertensive subjects compared to normal subjects (p=.045).
More subjects had higher chronic stress (55.5%) than the median stress levels of the participants (Table 1).In female (60.9%) subjects recorded a significantly higher chronic stress (anxiety) state than male subjects (50%) (p=.017).Mean stress levels increased with age group category, peaking in the middle age group (28-39years) and then dropping in subjects above 39years (p=.036).
Among female hypertensive subjects, high stress was significantly more prevalent (57.14%) as compared with non-hypertensive female subjects (33.87%) (p=.036).This was however not seen in males.There was a positive association between hypertension with sodium intake (p<0.05)however negative association existed between hypertension and lysine intake per gram protein consumed (OR(CI): 1.06 (1.0 to 1.1), p<.05).BMI was also associated with hypertension (OR(CI): 1.0 (0.9 to 1.0), p<.05).The percent RDA met for dietary lysine, carbohydrate contribution to dietary energy and dietary diversity score of subjects had a negative association with body mass index (p<.05)(table 2).

Figure. 1 Distribution of malnutrition, hypertension and stress among male and female subjects
Males with higher anxiety recorded a significantly lower mean age (p=.035), lower percentage body fat (p=.029) and their diet had lower animal protein (p=.003) content than normal males.They however recorded a significantly higher cereal protein (p=.021) making up their diet.This was not seen in females with high chronic stress levels.

DISCUSSION
It was observed that generally the prevalence of overweight/obesity was high, with 21.3% of the population overweight and 14% obese.Prevalence of overweight and obesity together was about 35% of the study subjects.Obesity in the subjects studied was much higher than that recorded (5.5%) by Biritwum 16 but same as that recorded by Amoah. 17This prevalence rate confirms the literature explanation of an increasing prevalence of obesity in developing countries.About 28.4% of the study populations were hypertensive with a further 36.4% of them also being pre-hypertensive.The high levels of hypertension and pre-hypertension in this study confirms report by Amoah, 1 which recorded a 28.4% crude prevalence of hypertension in Accra, with only 34% of hypertensive subjects were aware of their status, 18% were treated and only 4% were controlled.
However, in this study, over 98% of hypertensive subjects in study population did not know their diseased condition and hence were not under any form of treatment.Overweight/obesity is a significant risk of hypertension in individuals and it has been documented that the risk of developing elevated blood pressure is two to six times higher in overweight than in normal-weight persons. 5It is therefore not surprising that a similar trend was found in this study were hypertension was associated with overweight/obesity (p<0.05).
Hypertension was higher among males than in females.This was expected as males had a higher dietary sodium and alcohol consumption and this puts them at a greater risk of developing hypertension.Mahan and Escott-Stamp 5 reported that, pre-hypertensive individuals have a higher future risk of developing hypertension than normal subjects.In total, hypertensive and prehypertensive subjects make up 70% of males and 59.3% of female subjects in the study population.This also shows a future worsening of hypertension prevalence in both groups.It may also be due to the higher than normal level of sodium and low level of potassium and calcium in their diet.In the Dietary Approach to Stop Hypertension (DASH) sodium study, a reduction in sodium intake caused stepwise decreases in blood pressure. 18Also because of its role in muscle function and because it is not produced in the body, dietary calcium is required in sufficient daily quantities to achieve and maintain appropriate blood pressure levels through optimal regulation of vascular resistance. 19Population studies have also shown an inverse relation of potassium intake to blood pressure, the prevalence of hypertension, or the risk of stroke. 5,20 was also observed that hypertension prevalence was higher in individuals with high chronic stress than in normal individuals, especially in female subjects.This indicates a higher risk of hypertension among individuals with higher chronic stress/anxiety than those with lower or normal stress/anxiety.Lekh 21 showed a significant decrease in both anxiety and blood pressure in hypertensive subjects after long term relaxation exercise.Mahan and Escott-Stamp 5 reported that stress initiates the release of aldosterone, a corticosteroid that causes renal sodium retention, and vasopressin (antidiuretic hormone), which stimulates renal tubular water resorption thereby increasing blood volume and subsequently blood pressure.
Lower dietary animal protein and higher cereal protein in high stress male subjects could be partly attributed to decreased essential amino acids with l-lysine being the most limiting amino acid.
Animal protein contains higher essential amino acids such as l-lysine amino acid, whiles cereal protein contains lower l-lysine amino acid.
Essential amino acids are important is stress response, 5 most of which are more available in animal protein and least available in cereal. 12Decreased levels of essential amino acids may also result in decreased synthesis and increased catabolism which may be responsible for the lower body fat stores in high stressed male subjects. 5gh protein consumption was associated with increased BMI in the study subjects.This could be because common protein foods (such as beans and meat) in the community are eaten with lots of fat and/oil (fried so increased calories).There was however a negative association between BMI and lysine percent RDA met, carbohydrate contribution to dietary energy and dietary diversity score of subjects.Increased fibre in more diversified and carbohydrate foods, compared to fatty or oily protein foods may account for this.

CONCLUSION
Hypertension prevalence in the study area was very high, more endemic in males than in females, and was associated with increased BMI, chronic stress or anxiety and dietary sodium intake.It was recommended that sodium restriction, stress management, management of overweight/obesity be made an integral part of hypertension prevention programs and management.Routine screening of hypertension, especially in peri-urban communities is also highly recommended in public health campaigns.
1(2%) hypertensive subject knew of the status

Table 2
Factors associated with body mass index in study subjects