Alcohol consumption, obesity and hypertension: Relationship patterns along different age groups in Uganda

Introduction Uganda is experiencing a significant increase in the prevalence of non-communicable diseases including hypertension and obesity. Frequent alcohol use is also highly prevalent in Uganda and is a key risk factor for both hypertension and obesity. This study determines the trends of frequent alcohol consumption, hypertension and obesity across different age groups, and the extent to which alcohol consumption affects the two. Methods The data were extracted from the 2014 National Non-communicable Diseases Risk Factor Survey (N=3,987) conducted among adults aged 18 to 69 years. Hypertension was defined as systolic blood pressure ≥140mmHG or diastolic blood pressure ≥90. Obesity was defined as body mass index >30 kg/m2. Frequent alcohol consumption was defined as alcohol use 3 or more times a week. Multivariable log binomial regression analysis was carried out for each of the two outcome variables against age group and controlled for frequency of alcohol consumption and few other independent factors. Non-parametric tests were used to compare trends of prevalence ratios across age groups. Modified Poisson regression was use in few instances when the model failed to converge. Results The results showed increasing trend in the prevalence of hypertension and frequent alcohol consumption but a declining trend for obesity along different age groups (p<0.01). Frequency of alcohol consumption did not significantly modify the age group-hypertension and age group-obesity relationships although the effect was significant with ungrouped age. There was significance in difference of fitted lines for hypertension prevalence ratios between frequent drinkers and mild drinkers and between abstainers and frequent drinkers. Alcohol consumption did not have any significant effect on obesity-age group relationship. Conclusion The results call for more research to understand the effect of alcohol on the hypertension-age relationship, and the obesity-age relationship. Why prevalence ratios for hypertension decline among those who take alcohol most frequently is another issue that needs further research.

7 121 measurements and the difference is minor. Frequent alcohol consumption was measured as 122 taking alcohol 3 or more times a week. 123 124 We used log binomial regression to model hypertension and obesity with key independent 125 variable being age group and key interaction variable as frequency of alcohol consumption.
126 Binomial models were preferred because they provide prevalence ratios directly. Secondly unlike 127 the alternative logistic regression log binomial models do not overestimate their coefficients 128 when the outcome of interest is a common occurrence [28,29] although they also have problems 129 of lack of convergence [19] . In the few times non-convergence occurred we used modified 130 Poisson regression which solves the problem but it is not also perfect since it produces 131 inconsistent variances [19]. Stata V14 software was used for analysis.  (Table 1). Two thirds were married or in relationship, but 177 marital status varied by sex. Two fifths had attained primary school, but among women a higher 178 proportion did not have any formal education. Nearly two thirds were employed, but among 179 men a higher percentage were employed than among women (75% vs. 58%). The median income 180 per month was 100,000(≈USD 30) and it was significantly higher among men (110,000) (USD 181 ≈33) than women (60,000) (≈18).
182 The level of frequent alcohol consumption (3 or more times a week) was 8.4% but it was 183 significantly higher among men (16%) than women (3.4%). Obesity was at 7.5% and it was 184 higher among women (10.9%) than men (2.4%). Hypertension level was at 18.4% and it did not 185 significantly differ by sex.  188 †15 refused to provide information NS-Not significant at 5% level † †only 3906 had blood pressure measurements.   Fig 2 shows the ratio of prevalence of hypertension at each age group to that at base age group of 219 18-20 by frequency of alcohol consumption. It's evident that after 40 years the hypertension 220 prevalence ratio across age groups among frequent drinkers was persistently lower than that 221 among those who did not take alcohol or drank moderately while trends for those who drank 222 moderately and those who never drank kept a steady rise at almost equal gradient. Beyond 60 223 years the ratio among the frequent drinkers dropped sharply to 0.8 rose slightly to 2.3.

consumption among both men and women
227 228 A closer examination of trends of prevalence ratios across age groups by sex showed that the 229 prevalence of hypertension across age groups is relatively lower among men that don't take 230 alcohol while it's the opposite among women (Fig 3). A Wilcoxon's rank sum test for the 231 difference was significant for men (p=0.03) but not for women (p>0.1). The figure left out those 232 who drank most frequently because they were too few to split by sex across age groups.  Table 3 shows prevalent ratios for obesity. The prevalence ratios of obesity reduced with 265 increasing age groups even after controlling for drinking patterns and marital status which were 266 significant in the bivariate analysis. A test of interaction with frequency of alcohol consumption 267 did not show any significance hence lack of influence on the obesity-age group relationship.
268   315 Lower prevalence of hypertension among frequent alcohol consumers compared to the abstainers 316 and infrequent drinkers is an issue that needs further investigation. One probable explanation is 317 the low number of respondents that were frequent alcohol consumers. In subsequent analysis by 318 sex the frequent consumers were left out because of small numbers.
319 Conclusion 320 We conclude, firstly, that the prevalence of frequent alcohol consumption increases across the 321 age groups at almost the same level with prevalence of hypertension until 50 years of age.
322 The frequency of alcohol consumption did not significantly modify the age group-hypertension 323 and obesity-age group relationships but the effect was significant with single years.
324 The prevalence of hypertension among frequent alcohol consumers is lower than that among 325 abstainers and infrequent/mild drinkers. This calls for further research as this is inconsistent with 326 several studies.