Physiology

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Predictions of normal forced vital capacity forced expired volume in one second in tanzanian children.
(Journal of UOEH, 1990-09-19) Mashalla, Yohana J.
Data on ventilatory function with particular reference to forced vital capacity (FVC), forced expired volume in one second (FEV1), and FEV1 expressed as percentage of FVC (FEV1%FVC) were obtained in 1413 healthy Tanzanian school children aged between 8 and 18 years. All subjects were nonsmokers and had neither symptoms nor history of cardiopulmonary diseases. Subjects in this study were significantly smaller in stature (P<0.05) and had smaller FVC and FEV1 (P<0.001) compared to values reported in children of comparable age and stature in the west. Lung volumes could best be described as a power function of standing height (y=a.Hb). The power derived from ln FVC on ln H were 3.39 and 3.24 for boys and girls respectively, while the power derived from ln FEV1, on ln H were 3.11 and 3.03 for boys and girls respectively. Constructed prediction formulae gave FEV1 and FVC which showed good agreement with FEV1 and FVC computed from prediction equations based on a similar mathematical model for black children in the Caribbean.
Pulmonary function parameters in asthma patients receiving oral ketotifen.
(1990-12-01) Mashalla, Yohana J.; Massele, Amos Y.
Ketotifen, an antianaphylactic and antihistamine drug was given orally to 31 asthma patients who had significant airflow limitation (mean FEV1% FVC = 65.1). 19 patients had extrinsic asthma and 12 patients had intrinsic asthma. Ketotifen was given in a dose of 1 mg twice daily for 16 weeks. At the end of this period, concomitant medication, frequency and severity of asthma attacks and mean lung function test results were analysed. The number of acute asthmatic attacks were reduced significantly from a mean of 7.1 attacks/week before treatment to 0.28 attacks/week after 16 weeks of treatment (P less than 0.001). The severity of attacks and the need to use concomitant bronchodilators agents were also reduced. Lung function improved following oral ketotifen administration as indicated by changes in FVC, FEV1, FEV1% FVC and PEF. FVC increased insignificantly (18.64 ml/week, P less than 0.3), while FEV1, FEV1% FVC and PEF improved significantly (33.45 ml/week, 0.76%/week and 5.52 l/min/week respectively, P less than 0.01). It was concluded that the relief which is often observed in patients suffering from bronchial asthma on ketotifen therapy is associated with an improvement in the lung function. Hence, ketotifen is effective in the prophylaxis of both extrinsic and intrinsic asthma.
Single breath assessment of bronchial responsiveness: A Comparison with the astograph method
(Journal of UOEH, 1991-12-12) Mashalla, Yohana J.
Bronchial responsiveness to inhaled doubling concentrations of acetylcholine using the astograph and single breathtechniques was assessed im 7 males and 11 females of the subjects had neither a historyof allcrgy nor whcczcs. Five<28%)haclallcrgic rhinitis and two (11%)had asthma. Seven (64%)ef the normal subjects, all asthmatic and sulijects with allergic rhinitis responded to inhaled acetylcholine. Respiratery conductance (Grs}and the one second ft)rsedexpired volume (FEVD expressed as percentages of thc baselinevalues were compared on a semilogarithmic scalc against cumulativc dosc. In most sub.iccts thc pattern of the curves showed c]ose similarities in the two methods. 'I'hebronchial sensitivity i.e.minimum cumulativc dosc of acctylcholinc justsuMcient to start a fallin the FEVL and Grs(C.i,,s and C.,t.Arespectively), showcd good corrclation (r=O,750,P
Changing relationship between FEV1 and height during adolescence.
(East African medical journal, 1992-05-01) Mashalla, Yohana J.
Forced expired volume in one second (FEV1), body weight, standing and sitting height, and chest dimensions were measured in 962 male and 674 female subjects aged between 9 and 20 years. Standing height and body weight correlated best with ventilatory indices in boys. In girls, standing height, body weight and chest circumference correlated more or less equally with ventilatory indices. Regression analysis of logarithmically transformed FEV1 on standing height were done. In the boys, the correlation coefficient between In FEV1 and in height increased from 0.34 at 9 years to 0.77 at 13 years of age, while girls appear to have reached a peak by 12 years of age. The mean allometric constant was 3.109 and 3.032 for male and female subjects respectively. However, age-specific allometric constants increased in the boys from 2.846 to a peak value of 4.045 at 16 years of age. In the girls, the constant increased to a peak value of 4.5 a year earlier than in boys. The log-log plot of FEV1 against standing height was nonlinear, becoming more curvilinear with increasing height. These findings reflect changes in body proportions and shape during adolescence with lung growth lagging behind growth in standing height.
Validity of the forced rebreathing method in the measurement of residual volume in patients with airflow limitation.
(East African medical journal, 1993-10-01) Mashalla, Yohana J.
The validity of the forced rebreathing method (FRM) in the measurement of residual volume (RVn) was assessed in two groups (28 and 12) of patients with significant airflow limitation. The mean FEV1% FVC% were 48.28%, SD = 8.91% and 54.3%, SD = 0.23% respectively. Patients performed at least 30 forced rebreathings into a bag and bottle system at about 28 breaths per minute. RVn per breath was regressed on breath and gas dilution was considered complete at the breath number where the regression line deviated from the nitrogen washout curve. Residual volume computed four breaths after the breath number where the regression line deviated from the curve were compared with results derived from helium dilution (RVHe), mouth (RVmo) and oesophageal (RVOeS) pressure changes in the body plethysmograph. The mean RVn was similar to RVHe (P > 0.98) and correlated well with RVHe (r = 0.908, P < 0.001). RVn and RVHe were significantly smaller than RVmo and RVoes (P < 0.001). The difference between RVn and RVmo was smaller than the difference with RVoes. RVmo was larger than RVoes (P < 0.001) and correlated well with RVoes (r = 0.939, P < 0.001). It is concluded that the FRM can be used with reasonable accuracy to measure residual volume in patients with airflow limitation, and has advantages over the plethysmographic and conventional helium dilution methods.
Normal peak expiratory flow in healthy adult male and female subjects.
(East African medical journal, 1994-02-01) Mashalla, Yohana J.
Peak expiratory flows (PEF) were measured in 830 and 270 healthy male and female subjects respectively using Autospiro model AS-500 (Minato, Japan) fitted with a heated pneumotachograph. All measurements were made in the standing position. Male subjects gave significantly larger PEF values than female subjects (P < 0.001), and PEF decreased with age at a rate of about 6.45% year. In the female subjects, PEF increased with age to reach a peak at about 32 years decreasing thereafter. The equations representing peak expiratory flow for this population are: PEF = 0.042H - 0.051A + 3.5 (l.s-1) for the male subjects and PEF = 0.014H + 4.445 (l.s-1) for female subjects, where H and A represent height (cm) and age (years) respectively. Regression equations for predicting PEF constructed in this study gave smaller PEF values than values from prediction equation derived from a Caucasian population. It is therefore, highly desirable that equations suitable for predicting PEF in our region be established and more research in this area is required to cover some of the minority tribes in our region.
Influence of airways resistance on the nitrogen washout from the lung during forced rebreathing.
(African journal of health sciences, 1994-05-01) Mashalla, Yohana J.
The forced rebreathing method was used to determine the rate of change (apparent increase) of residual volume (RV) per breath in a group of 64 healthy non-smokers, 449 healthy smokers and 28 patients with chronic obstructive pulmonary disease (COPD). The mean FEV(1)% FVC in the patients was 48.28% (SD= = 8.9%). The rate of breathing into the bag-bottle system was maintained at 28 breaths per minute for all subjects. An asymptote in the nitrogen washout curve was reached within 5 breaths in healthy subjects as compared to between 7-13 in patients with COPD. The mean apparent increase in RV average 11ml/breath, 15ml/breath and 18ml/breath in healthy non-smokers, smokers and patients with COPD respectively. The mean apparent increase in RV in healthy non-smokers approximated a normal resting oxygen consumption per minute. It was higher in healthy smokers and patients with COPD than in healthy non-smokers. It is concluded that because of a high airway resistance, the forced rebreathing increases the work of breathing in order to overcome resistance to gas flow in the airways. More energy is required and oxygen is removed from the bag-bottle system without a corresponding replacement with carbon dioxide. The volume of the bag-bottle system progressively decreases resulting in a high apparent increase in RV.
Coordinating health research to promote action: the Tanzanian experience.
(BMJ, 2000-09-30) Mashalla, Yohana J.
Developing countries carry 90% of the global burden of disease. Infections such as malaria and HIV are debilitating their economies by killing the young and economically productive workforce. Research is essential for health development, yet less than 10% of the annual global expenditure on health research is allocated to addressing developing countries' problems.1 Poor countries must face this challenge seriously. It is essential that they create strong national research infrastructures so that they can define priorities for health research priorities; influence national, regional, and global health agendas; and lobby for a more equitable allocation of resources. This paper discusses some of the barriers to establishing coordinated health research programmes in developing countries and describes how Tanzania has developed a new research model to try and overcome these.
Research involving human subjects: Ownership, control, and access to research medical records.
(Research gate, 2001-01) Mashalla, Yohana J.
For centuries the perception of research involving human subjects, has been beyond argument, and human subjects have volunteered unconditionally to participate in researches. The image of medical research has now become even more favourable because of the HIV pandemic, and demands from women and other groups that they be included in the surveys. However, researches which have not been well thought out, and or are improperly executed, may be associated with risks to the participating subjects. The risks range from possible exploitation, especially of vulnerable groups such as the sick, women, children, the poor, and other people, who for some reasons may not have the capacity to give informed consent. Research involving human subjects may also cause physical and or psychological damage to the participating subjects, especially where the integrity and cultural values of the individuals are transgressed. The Nuremberg Code, Declaration of Helsinki, CIOMS Guidelines on Biomedical Research, and other country specific codes, are among those commonly used as reference guidelines on research involving human subjects. While such guidelines have shown positive results, issues related to ownership, access, and control of research results, are still inadequately covered. It is expected that with research being associated with risks of varying severity, clear and precise guidance should be given on the rights of participating subjects to the results of the research. It should be borne in mind however, that whatever recommendations are to be made the autonomy and integrity of the participating subjects and their cultures should always be respected.
Proceedings of the seminar on health research ethics in Africa.
(Acta Tropica, 2001-01-15) Mashalla, Yohana J.
The first conference of the African Malaria Vaccine Testing Network (AMVTN) identified as a leading priority, the promotion of ethics in health research undertaken in Africa. The participants at the 1995 meeting expressed the need for mainly increasing awareness of ethics in health research and of reviewing current practices and existing guidelines. The conference also noted that there were very limited national health research capacity, and the continuing reliance on non-African participation in health research on African health issues, and the attendant short-comings thereof, including inherent ethics issues. From its founding about 5 years ago, AMVTN in all its capacity building endeavours, particularly in its workshops on study designs and methodology, good clinical practice (GCP), and data management, has identified promotion of ethics to be a top priority. This activity being such a major challenge required considerable preparations, which started in earnest during 1997. It was decided very early that a workshop would not suffice and a conference would lack sufficient focus. It was therefore decided to organize a Seminar on Health Research Ethics in Africa. After wide ranging consultations, the relevant topics and respective speakers were identified and invited.
The relation of oxidative DNA damage to hypertension and other cardiovascular risk factors in Tanzania.
(Journal of hypertension, 2001-03) Mashalla, Yohana J.
Objectives: To clarify the mechanism of involvement of oxidative stress in hypertensives, we investigated the relationship between the marker of oxidative DNA damage, urinary 8-hydroxy2′-deoxyguanosine (8-OHdG), and cardiovascular risk factors, such as hypertension and serum glycosylated hemoglobin (HbA1c), among Tanzanians aged 46-58 years who were not on antihypertensive medication. Design and methods: Sixty subjects (males/females, 28/32) were selected randomly from the subjects who completed a 24h urine collection in our epidemiological study at Dar es Salaam, Tanzania in 1998. The subjects were divided into two groups, hypertensive subjects (systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥90 mmHg) and normotensive subjects (SBP <140 mmHg and DBP <90 mmHg) or hyperglycemic subjects (HbA1c ≥ 6.0%) and normoglycemic subjects (HbA1c< 6.0%). Biological markers from urine and blood were analyzed centrally in the WHO Collaborating Center. Results: The mean levels of HbA1c and 8-OHdG were significantly higher in the hypertensive subjects than in the normotensive subjects (P < 0.05). Urinary 8-OHdG was significantly higher in hyperglycemic subjects than in normoglycemic subjects. HbA1c was positively correlated with the 24-h urinary 8-OHdG excretions (r = 0.698, P < 0.0001). Conclusions These ®ndings suggest oxidative DNA damage is increased in hypertensive subjects, and there is a positive correlation between the level of blood glucose estimated as HbA1c and oxidative DNA damage.Hyperglycemia related to insulin resistance in hypertension in Tanzania is associated with increased urinary 8-OHdG. J Hypertens 19:529±533 & 2001 Lippincott Williams & Wilkins.
Cardiovascular risk factors in Tanzania: A revisit.
(Acta tropica, 2001-03-09) Mashalla, Yohana J.
In this assessment of cardiovascular risk factors, we examined the prevalence of selected risk factors according to the World Health Organisation (WHO) CARDIAC Study protocol and compared them with a similar study conducted more than a decade ago. The survey was carried out in Dar es Salaam (D, urban), Handeni (H, rural) and Monduli (Mo, semi-nomadic area). Subjects aged 47–57 were recruited randomly for blood pressure and anthropometrical measurements, 24 h urine collection and blood sampling. A structured questionnaire was used to obtain dietary information. The 1998 survey studied 446 subjects, while the 1987 survey included 496 men and women. The measured weight, body mass index (BMI) and prevalence of obesity (BMI≥30 kg/m2) increased significantly among women in the 1998 survey in rural Handeni and urban Dar. The overall prevalence of obesity was higher for women in the most recent survey (22.8%, P<0.0001). Diastolic blood pressure (DBP) was higher in the most recent survey for women in Handeni. The overall prevalence of hypertension (blood pressure>160/95 mmHg, or antihypertensive drug use), rose to 41.1% in 1998, (P<0.001) for men and to 38.7% (P<0.05) for women. The mean total serum cholesterol and prevalence of hypercholesterolaemia increased significantly in the most recent survey in the three studied areas. The overall prevalence of hypercholestrolaemia (serum cholesterol>5.2 mmol/l) was higher in the 1998 survey for both men (21.8%, P<0.0001) and women (54.0%, P<0.0001). The mean HDL cholesterol increased significantly in the most recent survey, with a significant reduction in the mean atherogenic index, though these were still at higher levels (men 5.8, P<0.0001; women 5.1, P<0.0001 vs. 1987). A strong positive correlation was observed between blood pressure (SBP and DBP) and body mass index, total serum cholesterol and sodium to potassium ratio. These data suggest that for the past decade there has been an increase in the mean levels and prevalence of selected cardiovascular risk factors in Tanzania.
Obesity and lipid profiles in middle aged men and women in Tanzania.
(East African medical journal, 2002-02) Mashalla, Yohana J.
Objective: To examine the relationship between obesity and lipid profiles and to compare the effects of total obesity and central adiposity on lipids in three locations in Tanzania. Design: Cross-sectional epidemiological study. Setting: Three areas in Tanzania: Dar es Salaam (urban), Handeni (rural) and Monduli (pastoralists), in August 1998. Subjects: Five hundred and forty five men and women from a random sample of 600 people aged 46-58 years. Main outcome measures: Mean BMI, waist circumference, WHR, TC, HDL-C, LDL-C, TG and LDL/HDL ratio. Prevalence rates of overweight, obesity, central obesity and dyslipidaemia. Results: As compared to men, women had higher BMl (24.7 versus 22.5 kg/m2, p<0.0001), waist circumference (92.4 versus 89.1 cm, p< 0.05), TC (4.9 versus 4.2 mmol/L, p<0.0001) and LDL-C (3.3 versus 2.6 mmol/L, p<0.0001). The urban population demonstrated higher levels of lipid factors than the rural population (TC, men 4.8 mmol/L; women 5.3 mmol/L, p<0.0001; TG, men 3.6 mmol/L; women 3.7 mmol/L, p<0.0001, LDL-C, men 2.8 mmol/L, p<0.0001). BMI and waist circumference correlated positively with serum TC, TG, and LDL-C in both genders. Stepwise regression analysis showed that BMI predicted triglyceride concentration in men (p<0.05) and women (p<0.0001). Waist circumference predicted levels of TC in women only (p<0.0001) and of LDL-C in both genders (men p<0.05, women p<0.0001). The prevalence of overweight, obesity and central obesity were significantly higher in urban than in rural areas in both men and women. Compared to lean subjects, obese men and women had significantly higher mean serum TC, TG, LDL-C and a higher prevalence of dyslipidaemia. The mean levels of TC, TG and LDL cholesterol increased across successive increases in BMI and waist circumference quintiles in both genders. Conclusion: Subjects from the urban area had greater lipid abnormalities related to obesity than those from the rural area and that, central adiposity had a greater effect on total cholesterol and LDL cholesterol among women than was BMI.
Prevalence of obesity and dyslipidemia in middle-aged men and women in Tanzania, Africa: relationship with resting energy expenditure and dietary factors.
(Journal of nutritional science and vitaminology, 2002-02-09) Mashalla, Yohana J.
The prevalence of obesity and dyslipidemia and the mean frequency of intake of selected dietary factors were studied in 545 participants aged 46-58y and living in three areas in Tanzania. The prevalence of obesity (body mass index of ≥30kg/m2) was 22.5% among women and 5.4% among men, p<0.001. Higher rates of obesity were observed in both men and women in an urban (U) area of Dar. The prevalence of dyslipidemia [(TC-HDL-C)/HDL-C>5] among men was higher in a pastoralists (P) population of the Maasai in Monduli (22.6%) than in Dar (9.6%) and rural (R) Handeni (7.3%, p<0.05). The mean resting energy expenditure (REE) was higher in subjects from the rural and pastoralists populations than in urban dwellers (0.024 kcal/min/kg, p<0.001). The three areas showed different dietary patterns with subjects from the urban area consuming coconut milk (4d/wk, p<0.001) and meat (2.5d/wk, p<0.05), more often than the rural population of Handeni which had the highest consumption of green vegetables (4.2d/wk, p<0.001). Participants from Monduli had the highest consumption of milk per day (1, 219mL/d, p<0.001). A simple correlation analysis showed that body mass index (BMI) correlated positively with the frequency of intake of coconut milk, fish and meat, and negatively with REE and milk consumption. Total cholesterol (TC) was negatively correlated with the frequency of intake of green vegetables, fish and the REE, and correlated positively with meat consumption and BMI in both genders. Independent of other factors, important contributors to obesity and dyslipidemia in this population were dietary factors such as meat (p<0.001) and fish (p<0.05), and a lower REE (p<0.05). These findings suggest that unhealthy diet and lower energy expenditure are important contributors to obesity and dyslipidemia in Tanzania.
Determinants of hyperleptinaemia in an African population.
(East African medical journal, 2003-02-17) Mashalla, Yohana J.
Objective: To examine the determinants for elevated plasma leptin concentration in normal weight (NW), obese (OB), and morbidly obese (MO) individuals in Tanzania. Design: Cross-sectional epidemiological study, the CARDIAC study. Setting: Three areas in Tanzania; Dar es Salaam, urban(U), Handeni, rural(R) and Monduli, pastoralists(P), in August 1998. Subjects: Five hundred and forty five participants from a random sample of 600 people aged 46-58 years. Main outcome measures: Plasma leptin concentrations, height, weight, body mass index (BMI), lipid profiles, haemoglobin Alc (HBA1c), and blood pressure (BP). Results: Plasma leptin concentrations were higher in women than in men (women; 16.0 ng/ mL, men; 3.1 ng/mL; p<0.0001). Women showed a higher mean body mass index (BMI), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) than men. In both genders, plasma leptin concentration, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), systolic BP (SBP) and diastolic BP (DBP) were significantly higher in OB than in NW participants. MO women had significantly higher leptin concentration, SBP and DBP compared with the other two groups. In NW men, log leptin concentrations showed a direct correlation with weight, BMI, HBAlc, TC, LDL-C, TG, SBP and DBP (all p<0.0001 except TG; p<0.001), while among NW women and OB men, weight and BMI correlated positively with log leptin (all p<0.05). OB women observed a positive correlation between log leptin and weight, BMI and LDL-C. Regression analysis indicated that among NW subjects, gender, BMI and TC explained 53.9% of the variation in log leptin. In OB subjects, gender, BMI and LDL-C explained 51.7% of the variability in leptin levels. No relationship was found between log leptin and CVD risk factors among MO subjects. Conclusion: The most important determinants for hyperleptinaemia in NW participants were gender, BMI, TC, while in addition to these LDL-C, was an important determinant of leptin concentration in OB individuals. In MO women, the high leptin concentrations did not reflect the amount of adipose stores.
Nutritional variation and cardiovascular risk factors in Tanzania - rural-urban difference.
(South African Medical Journal, 2003-03-18) Mashalla, Yohana J.
Objective: To assess the relationship between dietary factors and cardiovascular (CVD) risk factors in middle-aged men and women, in urban, rural and pastoral settings in Tanzania. Design: Cross-sectional epidemiological study designed according to the protocol of the World Health Organisation (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) study. Setting: Three centres in Tanzania, namely Dares Salaam (urban), Handeni (rural) and Monduli (pastoral population). Subjects. The subjects, aged 47 - 57 years, were recruited randomly from administrative lists available from each centre. Outcome measures: Blood pressure (BP) was measured using a centrally calibrated automatic BP machine (Khi machine). Dietary history of the participants was obtained using a standard questionnaire designed on the basis of a seven-day recall system. Height, weight, serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDLC), haemoglobin A 1 c, sodium, potassium and magnesium were measured. Results: The prevalence of hypertension (BP:?: 140/90 mmHg or antihypertensive drug use), obesity (body mass index (BMI):?: 30 kg/m') and hypercholesterolaemia (TC > 5.2 mmol/l) were lowest in the rural area. Consumption of green vegetables, milk, coconut milk, meat, and fish varied significantly between the three areas. Important determinants for BP among men were BMI (p < 0.001), and salt intake (p < 0.05). Among women, TC (p < 0.05), age (p < 0.05), BMI (p < 0.001) and coconut milk consumption (p < 0.001)were important BP determinants. Salt intake was positively associated with systolic BP (SBP) and diastolic BP (DBP) in men but not among women (both SBP and DBP p < 0.05 respectively). Dietary determinants of serum TC were meat, fish and green vegetable consumption. Conclusion: Differences in dietary habits contributed significantly to the urban-rural-pastoral variations in CVD risk pattern in Tanzania
Dust exposure during small-scale mining in Tanzania: a pilot study.
(Annals of Occupational Hygiene, 2003-04-01) Mashalla, Yohana J.
Small-scale mining in developing countries is generally labour-intensive and carried out with low levels of mechanization. In the Mererani area in the northern part of Tanzania, there are about 15 000 underground miners who are constantly subjected to a poor working environ- ment. Gemstones are found at depths down to 500 m. The objectives of this pilot study were to monitor the exposure to dust during work processes, which are typical of small-scale mining in developing countries, and to make a rough estimation of whether there is a risk of chronic pulmonary diseases for the workers. Personal sampling of respirable dust (n = 15) and ‘total’ dust (n = 5) was carried out during three consecutive days in one mine, which had a total of 50 workers in two shifts. Sampling started immediately before the miners entered the shaft, and lasted until they reappeared at the mine entrance after 5–8 h. The median crystalline silica content and the combustible content of the respirable dust samples were 14.2 and 5.5%, respectively. When drilling, blasting and shov- elling were carried out, the exposure measurements showed high median levels of respirable dust (15.5 mg/m3), respirable crystalline silica (2.4 mg/m3), respirable combustible dust (1.5 mg/m3) and ‘total’ dust (28.4 mg/m3). When only shovelling and loading of sacks took place, the median exposures to respirable dust and respirable crystalline silica were 4.3 and 1.1 mg/m3. This study shows that the exposure to respirable crystalline silica was high during under- ground small-scale mining. In the absence of personal protective equipment, the miners in the Mererani area are presumably at a high risk of developing chronic silicosis.
Cement Dust Exposure and Ventilatory Function Impairment: An Exposure– Response Study.
(Journal of occupational and environmental medicine, 2004-07) Mashalla, Yohana J.
We investigated cumulative total cement dust exposure and ventilatory function impairment at a Portland cement factory in Tanzania. All 126 production workers were exposed. The control group comprised all 88 maintenance workers and 32 randomly chosen office workers. Exposed workers had significantly lower forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), FEV1/FVC, FVC%, FEV1% and PEF%, than controls adjusted for age, duration of employment, height, and pack-years. Cumulative total dust exposure was significantly associated with reduced FVC, forced expiratory volume in 1 second, and peak expiratory flow rate adjusted for age, height and pack-years. Cumulative total dust exposure more than 300 mg/m3 year versus lower than 100 mg/m3 years was significantly associated with increased risk of developing airflow limitation (odds ratio = 9.9). The current occupational exposure limit for total cement dust (10 mg/m3) appears to be too high to prevent respiratory health effects among cement workers.
Changing the debate about health research for development.International health research awards recipients
(Journal of public health policy, 2004-12-10) Mashalla, Yohana J.
We represent ten groups of citizens and researchers from low- and middle-income countries who were recipients of International Health Research Awards (IHRA) presented at the Bangkok Conference on International Health Research for Development, 2000. The IHRA, funded by the Rockefeller Foundation and administered by the World Health Organization, recognized the need for us to find effective ways of solving our countries' health problems and acknowledged the special environmental constraints we face in conducting research and exploiting the results. We used this funding to explore alternative ways for harnessing largely untapped resources in our countries to generate and apply knowledge to improve people's health and address inequalities. In the Bangkok Declaration, we joined many others to express our commitment to research as a vital force for health of all of our people. Six of our ten projects explored, for particular themes or health topics, ways of extending the benefits of research to special groups or populations. Four more proposed specific approaches to consolidate national research policy and systems for allocating public research funds and managing research. From our collective reflection about what we have learned, we note ways in which our experiences represent change, particularly expansion of the traditional boundaries of research: –broadening the research agenda by adding new topics, more voices and more perspectives than has been the norm in our settings –expanding capacity to design and conduct research by preparing new groups of researchers to pose questions, design and carry out studies, and by engaging more partners and disciplines in addressing national priorities –extending dissemination of research results, especially by using websites and mass media to reach decision makers and broader segments of the public –encouraging uptake of research for policy and practice. We want research to improve the health of our societies' most disadvantaged groups and to engage them in the process. Our work benefited immeasurably from networks and other forms of collaboration that our grants helped to support—and supported to an extent that was unusual compared to other forms of research funding. We linked our national and regional collaborations to global efforts, but endeavored to do so without being driven or preempted by the latter. We are optimistic about the value of our experiences, but remain acutely aware of the unfinished agenda—an agenda that we incorporate into A CHALLENGE and A CALL for future action. We challenge ourselves, and others, to evaluate the effectiveness of our approaches to research for improving health systems and population health. We call on policy makers to adopt an evidence-based approach and to ensure that health systems are equipped to use rigorous research methods to embrace and analyze information from all participants. We close by asking donors and other international agencies for more flexible support so that we can benefit from global collaboration while maintaining our own priorities and building national and regional infrastructures to implement and evaluate new ways of doing research.
Research ethics in developing countries
(BMJ Open, 2005-05) Mashalla, Yohana J.
The profession of epidemiology has at its foundation the maintenance, enhancement, and promotion of public health by better understanding the determinants of disease.epidemiologists therefore, in the course of practice, should be accountable for the work that they perform as guided by national and international ethics guidelines, policies and established policies. In the recent years, there has been a growing trend for collaborative research between institutions in the north and those in the south. This is a result of changing pattern of diseases, emerging diseases (for example EBOLA) and re-emerging conditions (for example tuberculosis). Cultural diversity, different working environments, national policies, and guidelines are some of the issues that may influence research ethics in collaborative research. While research ethics may be well established in institutions in the developed countries, the same is not in many developing countries.Lack of established structures for dealing with research ethics, poorly constituted ethics review boards, underfunding of research review boards, lack of training of human resources on research ethics, poor research management, lack of awareness of international ethical guidelines and standards, inadequate knowledge of the rights of subjects, illiteracy, poverty, and increased of vulnerability of communities are major challenges of research ethics in developing countries. It is suggested that researchers from the north and those from the south should work closely to understand the context of research ethics in developing countries and facilitate promotion of ethical standards in research in developing countries.

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