Reliable quantification of the burden of stroke in low- and middle-income (LMI) countries is diff... more Reliable quantification of the burden of stroke in low- and middle-income (LMI) countries is difficult as population-based surveillance reports are scarce and may vary considerably in methodology. We aimed to evaluate all available primary stroke surveillance studies by applying components of a benchmark protocol (WHO STEPwise approach to stroke surveillance) and quantify the reported burden of stroke in LMI settings. Electronic databases Medline, Embase, Scopus, and Web of Knowledge were searched for population-based surveillance studies. Studies conducted in the LMI countries that reported on incident stroke were included. Data were extracted from each study using a prestructured format. Information on epidemiologic measures including crude and age-adjusted incidence rates, person-years, admission rates, case fatality rates, death certification, autopsy rates, measures of disability, and other study-specific information, in line with WHO STEPS stroke protocol, were recorded. Age-adjusted incidence rate data of stroke were combined using random-effects meta-analyses. We identified 7 studies that reported on burden of stroke in 9 LMI countries, including aggregate information from 1,711,372 participants collected over 5,240,923 person-years. The age-adjusted incidence rates across the LMI countries varied widely, with the burden of total first-ever strokes ranging from 41 to 909 events per 100,000 person-years. Systematic evaluation of all available primary surveillance studies, particularly in the context of WHO STEPS guidelines, indicates inadequate adherence to standardized surveillance methodology in LMI countries. Incorporation of standardized approaches is essential to enhance generalizability and estimate stroke burden accurately in these resource-poor settings.
High protein intake in early childhood is associated with obesity, suggesting possible adverse ef... more High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In genera...
Journal of Clinical and Experimental Neuropsychology, 2015
The cognitive reserve hypothesis suggests that across the lifespan, higher education, regular par... more The cognitive reserve hypothesis suggests that across the lifespan, higher education, regular participation in social or mentally stimulating activities, and complexity of occupation increase an individual's resistance to dementia. However, there is currently no consensus regarding how to assess or measure cognitive reserve. Method: We performed a systematic review of reviews focused on the concept of cognitive reserve to examine key elements of the definition and highlight limitations. We searched Embase.com, MEDLINE (OvidSP), the Cochrane Library, Web of Science, Scopus, Google Scholar, and PubMed. Results: Five systematic reviews were identified. These incorporated findings from cohort, cross-sectional, and case-control studies, and the outcomes examined included Alzheimer's disease, vascular dementia, nonspecified dementia, all dementias, and cognitive decline or cognitive impairment. Education, occupation, and leisure or mentally stimulating activities were suggested to supply cognitive reserve and offer a protective effect against the risk of dementia. Premorbid IQ and socioeconomic status have not been investigated as thoroughly and showed inconsistent results. Two of the reviews showed that when combining different indicators in the analyses/definition, including education, occupation, mentally stimulating activities, and premorbid IQ, cognitive reserve had a protective effect against cognitive decline. However, other indicators may also supply the reserve, including dietary habits and genetic indicators, but research is lacking with regard to creating a full cognitive reserve model. Conclusions: This review highlights the lack of consensus regarding a definition of cognitive reserve. Further research is required to clarify how the indicators already identified may provide cognitive reserve and offer a protective effect against dementia. Agreement on the indicators that constitute the cognitive reserve model is needed before testing possible interventions that may increase the reserve supply and improve cognition.
Persons with cognitive impairment, as assessed by cognitive tests, are at a higher risk of stroke... more Persons with cognitive impairment, as assessed by cognitive tests, are at a higher risk of stroke. Subjective memory complaints might be an earlier marker for stroke, especially in persons with higher education. Their cognitive reserve might mask their cognitive impairment during cognitive testing. In a population-based setting, we investigated the association between subjective memory complaints and stroke. We simultaneously investigated the association between Mini-Mental State Examination and stroke. We also assessed whether these associations varied with educational level. 9152 participants from the Rotterdam Study (baseline 1990-1993 or 2000-2001) completed the subjective memory complaints questionnaire and underwent Mini-Mental State Examination assessment. Subsequently, the entire cohort was followed for incident stroke until 2012. We used Cox proportional hazard models to estimate the associations between subjective memory complaints and Mini-Mental State Examination, with s...
Journal of epidemiology and community health, Jan 19, 2015
Breastfeeding has been related to better cognitive development in children. However, due to metho... more Breastfeeding has been related to better cognitive development in children. However, due to methodological challenges, such as confounding, recall bias or insufficient power, the mechanism and nature of the relation remains subject to debate. We included 3761 participants of a population-based cohort study from fetal life onwards and examined the association of breastfeeding duration with non-verbal intelligence in children of age 6 years. Maternal and paternal lifestyle, sociodemographic factors, child factors and maternal IQ were tested for their confounding effects on the association. We observed an initial association between breastfeeding duration and child IQ conferring an advantage of 0.32 (0.20 to 0.44) points for each additional month of breastfeeding. This association strongly attenuated to 0.09 (-0.03 to 0.21) points after adjustment for child factors, sociodemographic factors, parental lifestyle factors and maternal IQ. Similarly, the associations with breastfeeding dura...
Objective: With increasing life expectancy, there is a focus on "healthy ageing". Most activities... more Objective: With increasing life expectancy, there is a focus on "healthy ageing". Most activities in this area focus on the elderly. However, the ageing process starts much earlier. Childhood offers an important window to lay a base for future healthy ageing. Thus, to address the full ageing process, we should include younger populations in ageing research.
Despite the overwhelming evidence supporting the effectiveness of antihypertensive medication, hy... more Despite the overwhelming evidence supporting the effectiveness of antihypertensive medication, hypertension remains poorly controlled in low and middle-income countries (LMICs). Lifestyle intervention studies reporting effects on blood pressure published from January 1977 to September 2012 were searched on various databases. From the 6211 references identified, 52 were included in the systematic review (12, 024 participants) and 43 were included in the meta-analysis (in total 6779 participants). We calculated and pooled effect sizes in mmHg with random-effects models. We grouped interventions into behavioral counseling (1831 participants), dietary modification (1831 participants), physical activity (1014 participants) and multiple interventions (2103 participants). Subgroup analysis and meta-regression were used to evaluate origins of heterogeneity. Lifestyle interventions significantly lowered blood pressure levels in LMIC populations, including in total 6779 participants. The changes achieved in SBP (95% confidence interval) were: behavioral counseling -5.4 (-10.7, -0.0) mmHg, for dietary modification -3.5 (-5.4, -1.5) mmHg, for physical activity -11.4 (-16.0, -6.7) mmHg and for multiple interventions -6.0 (-8.9, -3.3) mmHg. The heterogeneity was high across studies and the quality was generally low. Subgroup analyses showed smaller samples reporting larger effect sizes; intervention lasting less than 6 months showed larger effect sizes and intention-to-treat analysis showed smaller effect sizes Lifestyle interventions may be of value in preventing and reducing blood pressure in LMICs. Nevertheless, the overall quality and sample size of the studies included were low. Improvements in the size and quality of studies evaluating lifestyle interventions are required.
Available literature suggests that both vitamin D and calcium may be associated with a wide range... more Available literature suggests that both vitamin D and calcium may be associated with a wide range of non-skeletal outcomes. However, epidemiological evidence supporting their individual associations with incident cerebrovascular disease is scarce. We conducted a systematic review and meta-analysis of prospective cohort studies, published before February 2012 and sought from MEDLINE, EMBASE, BIOSIS and the Science Citation Index databases, and reported cerebrovascular disease (defined as any fatal or non-fatal ischemic stroke, hemorrhagic stroke, cerebrovascular accident or transient ischemic attack) by circulating vitamin D (25-hydroxy vitamin D [25(OH)D] as active metabolite) and calcium levels. Two independent investigators abstracted information on 25(OH)D and calcium, cerebrovascular outcomes and other characteristics from selected studies. Relative risks (RRs) were pooled by both random and fixed effects meta-analyses and were further examined under different study-level characteristics. Publication bias was assessed with funnel plots and Egger's asymmetry test. From 5,778 initial references, nine unique prospective cohort studies met our inclusion criteria. Seven studies (involving 47,809 participants and 926 cerebrovascular events) focused on circulating 25(OH)D and 3 reported on circulating calcium (22,577 participants and 727 events). For 25(OH)D, in a comparison of individuals in the top third versus those in the bottom third at baseline, the combined RR for cerebrovascular disease, adjusted for several conventional risk factors, was 0.60 (95 % CI 0.48, 0.72). The corresponding RR in the prospective studies that reported on baseline circulating calcium levels for cerebrovascular disease was 1.40 (95 % CI 1.19, 1.64). There was no apparent evidence of heterogeneity or publication bias among included studies. Available data indicate that higher circulating level of vitamin D is associated with a decreased risk of cerebrovascular disease. Conversely, higher circulating calcium concentration is associated with an increased risk of cerebrovascular disease.
High protein intake in early childhood is associated with obesity, suggesting possible adverse ef... more High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In general, the quality of the included studies was low. Most studies were cross-sectional, and many did not control for potential confounders. No overall associations were observed between protein intake and insulin sensitivity or blood lipids. A few studies suggested an inverse association between dietary protein intake and BP, but evidence was inconclusive. Only four studies examined the effects of vegetable or animal protein intake, but with inconsistent results. In conclusion, the literature, to date provides insufficient evidence for effects of protein intake on BP, insulin sensitivity or blood lipids in children. Future studies could be improved by adequately adjusting for key confounders such as energy intake and obesity.
Reliable quantification of the burden of stroke in low- and middle-income (LMI) countries is diff... more Reliable quantification of the burden of stroke in low- and middle-income (LMI) countries is difficult as population-based surveillance reports are scarce and may vary considerably in methodology. We aimed to evaluate all available primary stroke surveillance studies by applying components of a benchmark protocol (WHO STEPwise approach to stroke surveillance) and quantify the reported burden of stroke in LMI settings. Electronic databases Medline, Embase, Scopus, and Web of Knowledge were searched for population-based surveillance studies. Studies conducted in the LMI countries that reported on incident stroke were included. Data were extracted from each study using a prestructured format. Information on epidemiologic measures including crude and age-adjusted incidence rates, person-years, admission rates, case fatality rates, death certification, autopsy rates, measures of disability, and other study-specific information, in line with WHO STEPS stroke protocol, were recorded. Age-adjusted incidence rate data of stroke were combined using random-effects meta-analyses. We identified 7 studies that reported on burden of stroke in 9 LMI countries, including aggregate information from 1,711,372 participants collected over 5,240,923 person-years. The age-adjusted incidence rates across the LMI countries varied widely, with the burden of total first-ever strokes ranging from 41 to 909 events per 100,000 person-years. Systematic evaluation of all available primary surveillance studies, particularly in the context of WHO STEPS guidelines, indicates inadequate adherence to standardized surveillance methodology in LMI countries. Incorporation of standardized approaches is essential to enhance generalizability and estimate stroke burden accurately in these resource-poor settings.
High protein intake in early childhood is associated with obesity, suggesting possible adverse ef... more High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In genera...
Journal of Clinical and Experimental Neuropsychology, 2015
The cognitive reserve hypothesis suggests that across the lifespan, higher education, regular par... more The cognitive reserve hypothesis suggests that across the lifespan, higher education, regular participation in social or mentally stimulating activities, and complexity of occupation increase an individual's resistance to dementia. However, there is currently no consensus regarding how to assess or measure cognitive reserve. Method: We performed a systematic review of reviews focused on the concept of cognitive reserve to examine key elements of the definition and highlight limitations. We searched Embase.com, MEDLINE (OvidSP), the Cochrane Library, Web of Science, Scopus, Google Scholar, and PubMed. Results: Five systematic reviews were identified. These incorporated findings from cohort, cross-sectional, and case-control studies, and the outcomes examined included Alzheimer's disease, vascular dementia, nonspecified dementia, all dementias, and cognitive decline or cognitive impairment. Education, occupation, and leisure or mentally stimulating activities were suggested to supply cognitive reserve and offer a protective effect against the risk of dementia. Premorbid IQ and socioeconomic status have not been investigated as thoroughly and showed inconsistent results. Two of the reviews showed that when combining different indicators in the analyses/definition, including education, occupation, mentally stimulating activities, and premorbid IQ, cognitive reserve had a protective effect against cognitive decline. However, other indicators may also supply the reserve, including dietary habits and genetic indicators, but research is lacking with regard to creating a full cognitive reserve model. Conclusions: This review highlights the lack of consensus regarding a definition of cognitive reserve. Further research is required to clarify how the indicators already identified may provide cognitive reserve and offer a protective effect against dementia. Agreement on the indicators that constitute the cognitive reserve model is needed before testing possible interventions that may increase the reserve supply and improve cognition.
Persons with cognitive impairment, as assessed by cognitive tests, are at a higher risk of stroke... more Persons with cognitive impairment, as assessed by cognitive tests, are at a higher risk of stroke. Subjective memory complaints might be an earlier marker for stroke, especially in persons with higher education. Their cognitive reserve might mask their cognitive impairment during cognitive testing. In a population-based setting, we investigated the association between subjective memory complaints and stroke. We simultaneously investigated the association between Mini-Mental State Examination and stroke. We also assessed whether these associations varied with educational level. 9152 participants from the Rotterdam Study (baseline 1990-1993 or 2000-2001) completed the subjective memory complaints questionnaire and underwent Mini-Mental State Examination assessment. Subsequently, the entire cohort was followed for incident stroke until 2012. We used Cox proportional hazard models to estimate the associations between subjective memory complaints and Mini-Mental State Examination, with s...
Journal of epidemiology and community health, Jan 19, 2015
Breastfeeding has been related to better cognitive development in children. However, due to metho... more Breastfeeding has been related to better cognitive development in children. However, due to methodological challenges, such as confounding, recall bias or insufficient power, the mechanism and nature of the relation remains subject to debate. We included 3761 participants of a population-based cohort study from fetal life onwards and examined the association of breastfeeding duration with non-verbal intelligence in children of age 6 years. Maternal and paternal lifestyle, sociodemographic factors, child factors and maternal IQ were tested for their confounding effects on the association. We observed an initial association between breastfeeding duration and child IQ conferring an advantage of 0.32 (0.20 to 0.44) points for each additional month of breastfeeding. This association strongly attenuated to 0.09 (-0.03 to 0.21) points after adjustment for child factors, sociodemographic factors, parental lifestyle factors and maternal IQ. Similarly, the associations with breastfeeding dura...
Objective: With increasing life expectancy, there is a focus on "healthy ageing". Most activities... more Objective: With increasing life expectancy, there is a focus on "healthy ageing". Most activities in this area focus on the elderly. However, the ageing process starts much earlier. Childhood offers an important window to lay a base for future healthy ageing. Thus, to address the full ageing process, we should include younger populations in ageing research.
Despite the overwhelming evidence supporting the effectiveness of antihypertensive medication, hy... more Despite the overwhelming evidence supporting the effectiveness of antihypertensive medication, hypertension remains poorly controlled in low and middle-income countries (LMICs). Lifestyle intervention studies reporting effects on blood pressure published from January 1977 to September 2012 were searched on various databases. From the 6211 references identified, 52 were included in the systematic review (12, 024 participants) and 43 were included in the meta-analysis (in total 6779 participants). We calculated and pooled effect sizes in mmHg with random-effects models. We grouped interventions into behavioral counseling (1831 participants), dietary modification (1831 participants), physical activity (1014 participants) and multiple interventions (2103 participants). Subgroup analysis and meta-regression were used to evaluate origins of heterogeneity. Lifestyle interventions significantly lowered blood pressure levels in LMIC populations, including in total 6779 participants. The changes achieved in SBP (95% confidence interval) were: behavioral counseling -5.4 (-10.7, -0.0) mmHg, for dietary modification -3.5 (-5.4, -1.5) mmHg, for physical activity -11.4 (-16.0, -6.7) mmHg and for multiple interventions -6.0 (-8.9, -3.3) mmHg. The heterogeneity was high across studies and the quality was generally low. Subgroup analyses showed smaller samples reporting larger effect sizes; intervention lasting less than 6 months showed larger effect sizes and intention-to-treat analysis showed smaller effect sizes Lifestyle interventions may be of value in preventing and reducing blood pressure in LMICs. Nevertheless, the overall quality and sample size of the studies included were low. Improvements in the size and quality of studies evaluating lifestyle interventions are required.
Available literature suggests that both vitamin D and calcium may be associated with a wide range... more Available literature suggests that both vitamin D and calcium may be associated with a wide range of non-skeletal outcomes. However, epidemiological evidence supporting their individual associations with incident cerebrovascular disease is scarce. We conducted a systematic review and meta-analysis of prospective cohort studies, published before February 2012 and sought from MEDLINE, EMBASE, BIOSIS and the Science Citation Index databases, and reported cerebrovascular disease (defined as any fatal or non-fatal ischemic stroke, hemorrhagic stroke, cerebrovascular accident or transient ischemic attack) by circulating vitamin D (25-hydroxy vitamin D [25(OH)D] as active metabolite) and calcium levels. Two independent investigators abstracted information on 25(OH)D and calcium, cerebrovascular outcomes and other characteristics from selected studies. Relative risks (RRs) were pooled by both random and fixed effects meta-analyses and were further examined under different study-level characteristics. Publication bias was assessed with funnel plots and Egger's asymmetry test. From 5,778 initial references, nine unique prospective cohort studies met our inclusion criteria. Seven studies (involving 47,809 participants and 926 cerebrovascular events) focused on circulating 25(OH)D and 3 reported on circulating calcium (22,577 participants and 727 events). For 25(OH)D, in a comparison of individuals in the top third versus those in the bottom third at baseline, the combined RR for cerebrovascular disease, adjusted for several conventional risk factors, was 0.60 (95 % CI 0.48, 0.72). The corresponding RR in the prospective studies that reported on baseline circulating calcium levels for cerebrovascular disease was 1.40 (95 % CI 1.19, 1.64). There was no apparent evidence of heterogeneity or publication bias among included studies. Available data indicate that higher circulating level of vitamin D is associated with a decreased risk of cerebrovascular disease. Conversely, higher circulating calcium concentration is associated with an increased risk of cerebrovascular disease.
High protein intake in early childhood is associated with obesity, suggesting possible adverse ef... more High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In general, the quality of the included studies was low. Most studies were cross-sectional, and many did not control for potential confounders. No overall associations were observed between protein intake and insulin sensitivity or blood lipids. A few studies suggested an inverse association between dietary protein intake and BP, but evidence was inconclusive. Only four studies examined the effects of vegetable or animal protein intake, but with inconsistent results. In conclusion, the literature, to date provides insufficient evidence for effects of protein intake on BP, insulin sensitivity or blood lipids in children. Future studies could be improved by adequately adjusting for key confounders such as energy intake and obesity.
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Papers by Ayesha Sajjad