zimbabwe is in sub - saharan africa which is at the epicenter of the human immune deficiency virus ( hiv ) epidemic . according to unaids the prevalence of hiv in zimbabwe
has decreased to about 1 in 10 adults ( 2012 ) from a high one of almost 1 in 4 in 2002 . while the decline is commendable hiv infection still remains a major problem in zimbabwe with 14.3% of adults being hiv positive .  
the high disease burden of hiv has necessitated a rapid increase in the use of highly active antiretroviral therapy ( haart ) . as of 2012
, over 476 thousand hiv - infected zimbabweans were on haart compared to only 8000 in 2003 . in the zimbabwe national program , first line drug combinations include a dual combination of tenofovir / tdf / disoproxil fumarate ( gilead sciences , usa ) ; a nucleoside reverse transcriptase inhibitor ( nrti ) and lamivudine/3tc/2,3 dideoxy-3-thiacytidine ( glaxosmithkline and pfizer , uk ) , an nrti and a triple combination of tenofovir , lamivudine with nevirapine / xr / viramune ( boehringer ingelheim , usa ) a non - nucleoside reverse transcriptase inhibitor ( nnrti ) [ 3 , 4 ] . in the event of treatment failure the patients
are treated with second line drugs including zidovudine / azt ( company ) an nrti ; didanosine / ddi / videx ( bristol - myers squibb co , usa ) , an nrti together with lopinavir and ritonavir ; protease inhibitors ( pis ) also known as kaletra / aluvia ( abbot laboratories ) .  
haart has reduced both the morbidity and mortality of hiv - infected people due to aids .
however haart is reported to have adverse side effects , one of which is bone mineralization .
changes in serum levels of biochemical markers of bone metabolism have been shown elsewhere in experimental and clinical studies [ 57 ] .
a number of studies from various parts of the world have reported that haart may have effects on bone metabolism via vitamin d   and/or parathyroid hormone .
this has been linked to the greater risk of developing fractures in hiv - infected patients on haart .
evidence has also been shown in some studies linking current use of haart to low levels of vitamin d : calcidiol ( 25-hydroxycholecalciferol ) .
calcidiol is most commonly determined in measurements of vitamin d status because of its longer half - life than the active form of vitamin d : calcitriol ( 1,25 cholecalciferol ) .
osteopenia and osteoporosis are conditions involving the weakening of bones which differ in the degree to which bones weaken .
osteopenia and osteoporosis are common manifestations in haart - experienced patients and are both due to low bone mineral density . in a recent study of a large number of hiv - infected participants , 53.7% of the patients had osteopenia whilst 26.8% had osteoporosis [ 14 , 15 ] .
who recommends use of bone mineral density as a marker of bone disorders like osteopenia and osteoporosis .
a number of studies such as the one by de socio et al . have reported changes in bone density accompanied by changes in serum levels of phosphate and alkaline phosphate in hiv - infected participants before and after antiretroviral therapy [ 18 , 19 ] .
a european study showed that tenofovir increases bone turnover and decreases bone mineral density in treated hiv - infected adults .
results in a us study showed that protease inhibitors increase the incidence of osteopenia and osteoporosis in men .  
tenofovir , a drug recently introduced to zimbabwe 's first line treatment , has been associated with osteomalacia , low serum levels of phosphate , and elevated alkaline phosphate in a swiss study . a nigerian study provided evidence for an elevation in albumin levels due to haart .
this is in contradiction to southern india study that showed that 84% of patients on art had low levels of albumin ( < 28 
there is no published evidence for the bone effect of prescribed first and second lines haart regimens on zimbabweans .
the objective of this study was to provide evidence of changes in serum bone profiles , if any , in a zimbabwean population of women using currently prescribed haart regimens and compare them to a similar group of hiv - infected women who are not yet on haart ( table 2 ) .
the broad objective was to find a noninvasive and cheap method of detecting changes in bone metabolism in hiv - infected and haart - experienced patients in our resource - limited settings .
parirenyatwa group of hospitals is a group of public and teaching hospitals found in the capital city of zimbabwe .
the group of hospitals are referral hospitals servicing casualties from harare city centre and its environs , together with referred cases from a number of clinics around harare and other zimbabwean provinces and districts .
the clientele attending the parirenyatwa opportunistic infections ( oi ) clinic , the site of our study , is diverse in terms of geographical location , but many are from low - income groups .
those participants who were on haart were taking a combination of tenofovir , lamivudine and nevirapine for the first line treatment and zidovudine , didanosine , and lopinavir / ritonavir for second line treatment .
we sequentially recruited 40 hiv - infected women , aged 18 to 40 years who had been on first line haart for more than 6 months and consented to be part of our study .
40 hiv - infected women who were haart - nave were matched for age with the 40 consenting haart - experienced women .
all the women had no evidence of critical illness at the time of the study .   permission to work with the parirenyatwa oi clinic was sought from the clinical director of parirenyatwa group of hospitals , whilst ethical clearance was given by the joint research ethics committee of the parirenyatwa group of hospitals and university of zimbabwe ( jrec ) after they were satisfied that the research protocol was ethically sound .
participants gave written consent after being informed fully about their role , risks , and benefits in the study and being satisfied that their identities would be protected using anonymous numerical identifiers on all documents and specimen containers .  
consider 
 ( 1)n=[(z/2+z1)2(p1p2)2][p1(1p1)+(1p2 ) ] , 
 where n = minimum sample size , z = test statistic ( at 5% ) , p1 = proportion with desired characteristic ( 0.05 ) , z/2 = 1.96 , z1   , p1 = 0.63 , p2 = 0.28,n = ( ( 1.96 + 0.84)/(0.630.84))(0.63(1  0.63 ) + 0.28(1  0.28 ) ) = 27.14 = 28,final n = 28 + refusal rate ( refusal rate = 15% of n),n = 28 + 12.17 = 40.17 .
n = ( ( 1.96 + 0.84)/(0.630.84))(0.63(1  0.63 ) + 0.28(1  0.28 ) ) = 27.14 = 28 , final n = 28 + refusal rate ( refusal rate = 15% of n ) , n = 28 + 12.17 = 40.17 . 

therefore overall minimum sample size = 80 ( 40 on haart and 40 haart - nave ) .
blood was drawn into plain tubes by a phlebotomist at the clinic during patients ' routine visits .
serum was aliquoted into 2  ml cryotubes and stored at 20c for up to 20 days .  
serum samples were thawed once at room temperature , and analysis was carried out on a bs120 mindray chemistry analyzer .
the chemistry analyzer was calibrated , and then controls and samples were assayed for total calcium , magnesium , phosphate , and albumin . corrected calcium was calculated for participants with low albumin levels .
the mean assayed values for the female patients on haart ( together with the normal reference ranges ) were : total calcium 6.92  mg / dl ( reference range 8.809.50  mg / dl ) , magnesium 1.78  mg / dl ( reference range 1.462.68  mg / dl ) , phosphate 5.10  mg / dl ( reference range 1.805.10  mg / dl ) and albumin 2.87  mg / dl ( reference 2.805.30  mg / dl ) .
the means of the haart - nave women were ; total calcium 8.40  mg / dl , magnesium 2.55  mg / dl , phosphate 5.10  mg / dl and albumin 3.25  mg / dl .
there was no significant difference between total calcium levels in patients on haart and haart - nave patients .
however , the values of calcium for the two groups in our study fall below the normal range .
this contradicts with studies done in america where elevation in serum calcium levels in women on antiretroviral therapy including tenofovir was linked to an increase in bone loss .
our results seem to be in agreement with a different set of studies described in india that reported lower levels of the active form of vitamin d ( calcitriol ) , resulting in reduced intestinal calcium absorption .
their report , as we observed , described a decrease in serum calcium levels after haart initiation .
it becomes essential to measure levels of vitamin d in future studies , in order to answer the important question of whether haart affects bone metabolism via vitamin d.   there were other interesting differences in serum bone profiles of the women in our study .
magnesium and albumin levels were within normal ranges for both groups of women , but the haart - experienced had lower magnesium and albumin levels than the haart - nave patients .
our findings for magnesium do not however agree with two studies : a brazilian study that showed hypomagnesaemia occurring in 29% of patients on antiretroviral therapy   and a study done in nigeria that showed an elevation in serum albumin , months after antiretroviral therapy initiation .
our results for albumin do correlate with the findings of a study carried out in southern india , in which serum albumin levels were lower after antiretroviral therapy .  
phosphate levels were elevated in haart - nave patients , and their levels were above the normal range whilst the haart - experienced women have on average phosphate levels that fall within normal ranges .
our study contradicts with studies which showed a link between use of tenofovir and hypophosphatemia   and studies done in america that showed a decrease in serum phosphate due to reduced renal retention .  
it is important to improve this study by increasing the number of study sites , increasing the power by enlarging the sample size , and also measuring the levels of vitamin d ( calcidiol or calcitriol ) .
the results of this and future studies will be used to advocate for change in practice in treatment of hiv - infected women on haart .
clinicians and decision makers may have to consider giving patients on haart vitamin d supplements to avoid weakening of bones in zimbabweans on haart .
another study involving both men and women is also necessary in order to determine what serum bone profiles changes may be happening in men due to hiv infection and/or haart .
is serum bone profiling a potentially noninvasive , inexpensive method that can be used routinely to detect changes in bone metabolism in the hiv infected patients in our resource - limited setting ?
this study shows evidence of changes in serum bone profiles . a larger study that also aims to determine association between serum bone profiles and measurement of the who gold standard ( mineral bone density ) may help answer that question .
 antiretroviral therapy inhibits hiv replication , maintains health , and preserves life . 
 however , both antiretroviral therapy and hiv infection have been reported to have short- and long - term effects on bone metabolism . 
 a cross - sectional study was performed to compare serum bone profiles in hiv positive patients on highly active antiretroviral therapy and compare them to therapy - nave patients . 
 serum levels of calcium , magnesium , phosphate , and albumin were measured in 40 female participants on highly active antiretroviral therapy , recruited sequentially from parirenyatwa opportunistic infections clinic , harare , zimbabwe . 
 the 40 women were matched for age with 40 antiretroviral therapy - nave women . 
 magnesium , phosphate , and albumin levels were significantly higher in the therapy - nave than in therapy - experienced patients . 
 there was no statistically significant difference in calcium levels of the two groups of women . 
 evidence from this study suggests that highly active antiretroviral therapy lowers levels of magnesium , phosphate , and albumin but has no effect on levels of serum calcium . 
1. Introduction
2. Materials and Methods
3. Results
4. Conclusion