Suhad Bahijri

A century of trends in adult human height

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries. DOI: http://dx.doi.org/10.7554/eLife.13410.001

Beneficial effects of chromium in people with type 2 diabetes, and urinary chromium response to glucose load as a possible indicator of status.

No reliable method for the estimation of chromium (Cr) status is available yet. The aim of this study is to investigate the possibility of using urinary Cr response to glucose load as an indicator of Cr status. Seventy-eight non-insulin-dependent diabetes mellitus patients were divided randomly into two groups and given Cr supplements as brewer’s yeast and CrCl3 sequentially with placebo in between, in a double-blind, crossover design of four stages, each lasting 8 wk. At the beginning and end of each stage, subjects were weighed, their dietary data and drug dosage recorded, and blood and urine samples collected for analysis of glucose and urinary chromium (fasting and 2 h post-75-g glucose load) and fructosamine.The mean urinary Cr after the glucose load was significantly higher than the fasting mean at zero time (p<0.01). However, only 52 of the patients showed an obvious increase; the others showed a slight decrease or no change. Both supplements caused a significant increase in the means of urinary Cr and a significant decrease in the means of glucose and fructosamine. Only those subjects responding to Cr supplement by improved glucose control showed an increase in post-glucose-load urinary Cr over fasting level, after the supplement but not at zero time. Therefore, it was concluded that urinary Cr response to glucose load could be used as an indicator of Cr status.

The effects of coadministration of dietary copper and zinc supplements on atherosclerosis, antioxidant enzymes and indices of lipid peroxidation in the cholesterol-fed rabbit

It has previously been shown that dietary copper can modulate the extent of atherosclerosis in the thoracic aorta of cholesterol‐fed rabbits. The metabolism of copper and zinc are closely related, and it has been hypothesized that the balance of dietary copper to zinc may be important in determining coronary risk. Hence, we have investigated the interaction between dietary copper and zinc in atherogenesis in the New Zealand White rabbit. Juvenile male rabbits were randomly allocated to eight groups. Four groups were fed a normal chow diet with zinc (0.5%, w/w), copper (0.2%, w/w), copper plus zinc or neither in their drinking water for 12 weeks. Four other groups were fed a diet containing 0.25–1% (w/w) cholesterol plus zinc, copper, both or neither. Serum cholesterol of individual animals was maintained at approximately 20 mmol/l.

Recommendations for management of diabetes during Ramadan: update 2015

Since the first ADA working group report on the recommendations for management of diabetes during Ramadan in 2005 and our update in 2010, we received many inquiries asking for regular updates on information regarding education, nutritional habits and new oral and injectable agents that may be useful for the management of patients with diabetes during Ramadan. Patients can be stratified into their risk of hypoglycemia and/or complications prior to the start of the fasting period of Ramadan. Those at high risk of hypoglycemia and with multiple diabetic complications should be advised against prolonged fasting. Even in the lower hypoglycemia risk group, adverse effects may still occur. In order to minimize adverse side effects during fasting in patients with diabetes and improve or maintain glucose control, education and discussion of glucose monitoring and treatment regimens should occur several weeks prior to Ramadan. Agents such as metformin, thiazolidinediones and dipeptidyl peptidase-4 inhibitors appear to be safe and do not need dose adjustment. Most sulfonylureas may not be used safely during Ramadan except with extreme caution; besides, older agents, such as chlorpropamide or glyburide, should not be used. Reduction of the dosage of sulfonylurea is needed depending on the degree of control prior to fasting. Misconceptions and local habits should be addressed and dealt with in any educational intervention and therapeutic planning with patients with diabetes. In this regard, efforts are still needed for controlled prospective studies in the field of efficacy and safety of the different interventions during the Ramadan Fast.

Relative metabolic stability, but disrupted circadian cortisol secretion during the fasting month of Ramadan.

Background Chronic feeding and sleep schedule disturbances are stressors that exert damaging effects on the organism. Practicing Muslims in Saudi Arabia go through strict Ramadan fasting from dawn till sunset for one month yearly. Modern era Ramadan practices in Saudi Arabia are associated with disturbed feeding and sleep patterns, namely abstaining from food and water and increasing daytime sleep, and staying awake and receiving food and water till dawn. Hypothesis Strict Ramadan practices in Saudi Arabia may influence metabolism, sleep and circadian cortisol secretion. Protocol Young, male Ramadan practitioners were evaluated before and two weeks into the Ramadan. Blood samples were collected at 9.00 am and 9.00 pm for measurements of metabolic parameters and cortisol. Saliva was collected serially during the day for cortisol determinations. Results Ramadan practitioners had relative metabolic stability or changes expected by the pattern of feeding. However, the cortisol circadian rhythm was abolished and circulating insulin levels and HOMA index were increased during this period. Discussion The flattening of the cortisol rhythm is typical of conditions associated with chronic stress or endogenous hypercortisolism and associated with insulin resistance. Conclusions Modern Ramadan practices in Saudi Arabia are associated with evening hypercortisolism and increased insulin resistance. These changes might contribute to the high prevalence of chronic stress-related conditions, such as central obesity, hypertension, metabolic syndrome and diabetes mellitus type 2, and their cardiovascular sequelae observed in the Kingdom.

Impact of an individualized type 2 diabetes education program on clinical outcomes during Ramadan

Objective To determine if individualized education before Ramadan results in a safer fast for people with type 2 diabetes. Methods Patients with type 2 diabetes who received care from participating clinics in Egypt, Iran, Jordan and Saudi Arabia and intended to fast during Ramadan 2014 were prospectively studied. Twelve clinics participated. Individualized education addressed meal planning, physical activity, blood glucose monitoring and acute metabolic complications and when deemed necessary, provided an individualized diabetes treatment plan. Results 774 people met study criteria, 515 received individualized education and 259 received usual care. Those who received individualized education were more likely to modify their diabetes treatment plan during Ramadan (97% vs 88%, p<0.0001), to perform self-monitoring of blood glucose at least twice daily during Ramadan (70% vs 51%, p<0.0001), and to have improved knowledge about hypoglycemic signs and symptoms (p=0.0007). Those who received individualized education also reduced their body mass index (−1.1±2.4 kg/m2 vs −0.2±1.7 kg/m2, p<0.0001) and glycated haemoglobin (−0.7±1.1% vs −0.1±1.3%, p<0.0001) during Ramadan compared those who received usual care. There were more mild (77% vs 67%, p=0.0031) and moderate (38% vs 19%, p<0.0001) hypoglycemic events reported by participants who received individualized education than those who received usual care, but fewer reported severe hypoglycemic events during Ramadan (23% vs 34%, p=0.0017). Conclusions This individualized education and diabetes treatment program helped patients with type 2 diabetes lose weight, improve glycemic control and achieve a safer fast during Ramadan.

The prevalence of diabetes and prediabetes in the adult population of Jeddah, Saudi Arabia- a community-based survey

Background Type 2 (T2DM) is believed to be common in Saudi Arabia, but data are limited. In this population survey, we determined the prevalence of T2DM and prediabetes. Materials and Methods A representative sample among residents aged ≥ 18 years of the city of Jeddah was obtained comprising both Saudi and non-Saudi families (N = 1420). Data on dietary, clinical and socio-demographic characteristics were collected and anthropometric measurements taken. Fasting plasma glucose and glycated hemoglobin (HbA1c) were used to diagnose diabetes and prediabetes employing American Diabetes Association criteria. Multiple logistic regression analysis was used to identify factors associated with T2DM. Results Age and sex standardized prevalence of prediabetes was 9.0% (95% CI 7.5–10.5); 9.4% (7.1–11.8) in men and 8.6% (6.6–10.6) in women. For DM it was 12.1% (10.7–13.5); 12.9% (10.7–13.5) in men and 11.4% (9.5–13.3) in women. The prevalence based on World Population as standard was 18.3% for DM and 11.9% for prediabetes. The prevalence of DM and prediabetes increased with age. Of people aged ≥50 years 46% of men and 44% of women had DM. Prediabetes and DM were associated with various measures of adiposity. DM was also associated with and family history of dyslipidemia in women, cardiovascular disease in men, and with hypertension, dyslipidemia and family history of diabetes in both sexes. Discussion Age was the strongest predictor of DM and prediabetes followed by obesity. Of people aged 50 years or over almost half had DM and another 10–15% had prediabetes leaving only a small proportion of people in this age group with normoglycemia. Since we did not use an oral glucose tolerance test the true prevalence of DM and prediabetes is thus likely to be even higher than reported here. These results demonstrate the urgent need to develop primary prevention strategies for type 2 diabetes in Saudi Arabia.

Health impact of fasting in Saudi Arabia during Ramadan: association with disturbed circadian rhythm and metabolic and sleeping patterns.

Background Muslims go through strict Ramadan fasting from dawn till sunset for one month yearly. These practices are associated with disturbed feeding and sleep patterns. We recently demonstrated that, during Ramadan, circadian cortisol rhythm of Saudis is abolished, exposing these subjects to continuously increased cortisol levels. Hypothesis Secretory patterns of other hormones and metabolic parameters associated with cortisol, and insulin resistance, might be affected during Ramadan. Protocol Ramadan practitioners (18 males, 5 females; mean age ±SEM = 23.16±1.2 years) were evaluated before and two weeks into Ramadan. Blood was collected for measurements of endocrine and metabolic parameters at 9 am (±1 hour) and again twelve hours later. Results In Ramadan, glucose concentration was kept within normal range, with a significant increase in the morning. Mean morning concentration of leptin was significantly higher than pre-Ramadan values (p = 0.001), in contrast to that of adiponectin, which was significantly lower (p<0.001). These changes were associated with increased insulin resistance in morning and evening. Concentrations of hsCRP were lower during Ramadan than those during regular living conditions, however, normal circadian fluctuation was abolished (p = 0.49). Even though means of liver enzymes, total bilirubin, total protein and albumin were all decreased during Ramadan, statistically lower means were only noted for GGT, total protein, and albumin (p = 0.018, 0.002 and 0.001 respectively). Discussion Saudi Ramadan practitioners have altered adipokine patterns, typical of insulin resistance. The noted decreases of hsCRP, liver enzymes, total protein, and albumin, are most likely a result of fasting, while loss of circadian rhythmicity of hsCRP is probably due to loss of circadian cortisol rhythm. Conclusions Modern Ramadan practices in Saudi Arabia, which are associated with evening hypercortisolism, are also characterized by altered adipokines patterns, and an abolished hsCRP circadian rhythm, all likely to increase cardiometabolic risk.

Gut Microbiota: A Contributing Factor to Obesity

Obesity, a global epidemic of the modern era, is a risk factor for cardiovascular diseases (CVD) and diabetes. The pervasiveness of obesity and overweight in both developed as well as developing populations is on the rise and placing a huge burden on health and economic resources. Consequently, research to control this emerging epidemic is of utmost importance. Recently, host interactions with their resident gut microbiota (GM) have been reported to be involved in the pathogenesis of many metabolic diseases, including obesity, diabetes, and CVD. Around 1014 microorganisms reside within the lower human intestine and many of these 1014 microorganisms have developed mutualistic or commensal associations with the host and actively involved in many physiological processes of the host. However, dysbiosis (altered gut microbial composition) with other predisposing genetic and environmental factors, may contribute to host metabolic disorders resulting in many ailments. Therefore, delineating the role of GM as a contributing factor to obesity is the main objective of this review. Obesity research, as a field is expanding rapidly due to major advances in nutrigenomics, metabolomics, RNA silencing, epigenetics, and other disciplines that may result in the emergence of new technologies and methods to better interpret causal relationships between microbiota and obesity.

Increased insulin resistance is associated with increased urinary excretion of chromium in non-diabetic, normotensive Saudi adults

The role of trivalent chromium in improving glucose tolerance is well documented. Increased urinary chromium has been reported in type 2 diabetes mellitus, but it was not clear whether this had preceded diabetes mellitus, or was caused by it. Aim was to investigate the relationship between urinary chromium and the degree of insulin resistance in non-diabetic normotensive Saudi adults. 357 healthy adults aged 18–50 years were recruited randomly in a cross-sectional study design. Anthropometric and demographic information were taken. Insulin, glucose and free fatty acids were measured in fasting blood samples. Fasting urinary chromium and creatinine were also determined. Using modified QUICKI, subjects were labeled as high insulin resistant, or low insulin resistant. High insulin resistant subjects were matched for age and sex to low insulin resistant subjects. High insulin resistant subjects had higher mean BMI (p<0.001), mean waist circumference (p<0.01), and median urinary chromium (p<0.001) compared to low insulin resistant subgroup. Higher urinary chromium in high insulin resistant subgroup indicates a renal lesion leading to chromium deficiency and possibly diabetes mellitus eventually. Chromium supplementation might help to protect against the development of diabetes mellitus in this group of high insulin resistant non-diabetic Saudi individuals.