Zonal control on Holocene precipitation in northwestern Madagascar based on a stalagmite from Anjohibe

The Malagasy Summer Monsoon is an important part of the larger Indian Ocean and tropical monsoon region. As the effects of global warming play out, changes to precipitation in Madagascar will have important ramifications for the Malagasy people. To help understand how precipitation responds to climate changes we present a long-term Holocene speleothem record from Anjohibe, part of the Andranoboka cave system in northwestern Madagascar. To date, it is the most complete Holocene record from this region and sheds light on the nature of millennial and centennial precipitation changes in this region. We find that over the Holocene, precipitation in northwestern Madagascar is actually in phase with the Northern Hemisphere Asian monsoon on multi-millennial scales, but that during some shorter centennial-scale events such as the 8.2 ka event, Anjohibe exhibits an antiphase precipitation signal to the Northern Hemisphere. The ultimate driver of precipitation changes across the Holocene does not appear to be the meridional migration of the monsoon. Instead, zonal sea surface temperature gradients in the Indian Ocean seem to play a primary role in precipitation changes in northwestern Madagascar.

A neotropical perspective on the uniqueness of the Holocene among interglacials

Understanding how tropical systems have responded to large-scale climate change, such as glacial-interglacial oscillations, and how human impacts have altered those responses is key to current and future ecology. A sedimentary record recovered from Lake Junín, in the Peruvian Andes (4085 m elevation) spans the last 670,000 years and represents the longest continuous and empirically-dated record of tropical vegetation change to date. Spanning seven glacial-interglacial oscillations, fossil pollen and charcoal recovered from the core showed the general dominance of grasslands, although during the warmest times some Andean forest trees grew above their modern limits near the lake. Fire was very rare until the last 12,000 years, when humans were in the landscape. Here we show that, due to human activity, our present interglacial, the Holocene, has a distinctive vegetation composition and ecological trajectory compared with six previous interglacials. Our data reinforce the view that modern vegetation assemblages of high Andean grasslands and the presence of a defined tree line are aspects of a human-modified landscape.

Deciphering local and regional hydroclimate resolves contradicting evidence on the Asian monsoon evolution

The winter and summer monsoons in Southeast Asia are important but highly variable sources of rainfall. Current understanding of the winter monsoon is limited by conflicting proxy observations, resulting from the decoupling of regional atmospheric circulation patterns and local rainfall dynamics. These signals are difficult to decipher in paleoclimate reconstructions. Here, we present a winter monsoon speleothem record from Southeast Asia covering the Holocene and find that winter and summer rainfall changed synchronously, forced by changes in the Pacific and Indian Oceans. In contrast, regional atmospheric circulation shows an inverse relation between winter and summer controlled by seasonal insolation over the Northern Hemisphere. We show that disentangling the local and regional signal in paleoclimate reconstructions is crucial in understanding and projecting winter and summer monsoon variability in Southeast Asia.

Last glacial hydroclimate variability in the Yucatán Peninsula not just driven by ITCZ shifts

We reconstructed hydroclimate variability in the Yucatán Peninsula (YP) based on stalagmite oxygen and carbon isotope records from a well-studied cave system located in the northeastern YP, a region strongly influenced by Caribbean climate dynamics. The new stalagmite isotopic records span the time interval between 43 and 26.6 ka BP, extending a previously published record from the same cave system covering the interval between 26.5 and 23.2 ka BP. Stalagmite stable isotope records show dominant decadal and multidecadal variability, and weaker variability on millennial timescales. These records suggest significant precipitation declines in the broader Caribbean region during Heinrich events 4 and 3 of ice-rafted discharge into the North Atlantic, in agreement with the antiphase pattern of precipitation variability across the equator suggested by previous studies. On millennial timescales, the stalagmite isotope records do not show the distinctive saw-tooth pattern of climate variability observed in Greenland during Dansgaard-Oeschger (DO) events, but a pattern similar to North Atlantic sea surface temperature (SST) variability. We propose that shifts in the mean position of the Intertropical Convergence Zone (ITCZ), per se, are not the dominant driver of last glacial hydroclimate variability in the YP on millennial timescales but instead that North Atlantic SSTs played a dominant role. Our results support a negative climate feedback mechanism whereby large low latitude precipitation deficits resulting from AMOC slowdown would lead to elevated salinity in the Caribbean and ultimately help reactivate AMOC and Caribbean precipitation. However, because of the unique drivers of future climate in the region, predicted twenty-first century YP precipitation reductions are unlikely to be modulated by this negative feedback mechanism.

Glacial changes in sea level modulated millennial-scale variability of Southeast Asian autumn monsoon rainfall

Most paleoclimate studies of Mainland Southeast Asia hydroclimate focus on the summer monsoon, with few studies investigating rainfall in other seasons. Here, we present a multiproxy stalagmite record (45,000 to 4,000 years) from central Vietnam, a region that receives most of its annual rainfall in autumn (September-November). We find evidence of a prolonged dry period spanning the last glacial maximum that is punctuated by an abrupt shift to wetter conditions during the deglaciation at ~14 ka. Paired with climate model simulations, we show that sea-level change drives autumn monsoon rainfall variability on glacial-orbital timescales. Consistent with the dry signal in the stalagmite record, climate model simulations reveal that lower glacial sea level exposes land in the Gulf of Tonkin and along the South China Shelf, reducing convection and moisture delivery to central Vietnam. When sea level rises and these landmasses flood at ~14 ka, moisture delivery to central Vietnam increases, causing an abrupt shift from dry to wet conditions. On millennial timescales, we find signatures of well-known Heinrich Stadials (HS) (dry conditions) and Dansgaard-Oeschger Events (wet conditions). Model simulations show that during the dry HS, changes in sea surface temperature related to meltwater forcing cause the formation of an anomalous anticyclone in the Western Pacific, which advects dry air across central Vietnam, decreasing autumn rainfall. Notably, sea level modulates the magnitude of millennial-scale dry and wet phases by muting dry events and enhancing wet events during periods of low sea level, highlighting the importance of this mechanism to autumn monsoon variability.

Dynamic and thermodynamic influences on precipitation in Northeast Mexico on orbital to millennial timescales

The timing and mechanisms of past hydroclimate change in northeast Mexico are poorly constrained, limiting our ability to evaluate climate model performance. To address this, we present a multiproxy speleothem record of past hydroclimate variability spanning 62.5 to 5.1 ka from Tamaulipas, Mexico. Here we show a strong influence of Atlantic and Pacific sea surface temperatures on orbital and millennial scale precipitation changes in the region. Multiple proxies show no clear response to insolation forcing, but strong evidence for dry conditions during Heinrich Stadials. While these trends are consistent with other records from across Mesoamerica and the Caribbean, the relative importance of thermodynamic and dynamic controls in driving this response is debated. An isotope-enabled climate model shows that cool Atlantic SSTs and stronger easterlies drive a strong inter-basin sea surface temperature gradient and a southward shift in moisture convergence, causing drying in this region.

Regulation of gambling in Sub-Saharan Africa: findings from a comparative policy analysis

OBJECTIVES

Commercial gambling markets have undergone unprecedented expansion and diversification in territories across Sub-Saharan Africa (SSA). This gambling boom has popularised the uptake of gambling products in existing circuits of popular culture, sport and leisure and raised concerns about the extent to which state legislation is equipped to regulate the differentiated impacts of gambling on public health.

STUDY DESIGN

Comparative policy analysis.

METHODS

This article provides a systematic mapping of the regulatory environment pertaining to gambling across SSA. The review was conducted by obtaining and triangulating data from a desk review of online materials, consultation with regulatory bodies in each territory and the VIXIO Gambling Compliance database.

RESULTS

Gambling is legally regulated in 41 of 49 (83.6%) SSA countries, prohibited in 7 (14.3%) and is not legislated for in 1 (2.0%). Of those countries that regulate gambling, 25 (61.0%) countries had dedicated regulators and 16 (39.0%) countries regulated via a government department. Only 2 of 41 (4.9%) countries have published annual reports continuously since the formation of regulatory bodies, and 3 (7.3%) countries have published an incomplete series of reports since the formation. In 36 (87.8%) countries, no reports were published. Enforcement activities were documented by all five regulators that published reports.

CONCLUSION

The review uncovered a lack of coherence in regulatory measures and the need for more transparent public reporting across SSA territories. There are also variations in regulating online products and marketing, with most countries lacking apt guidelines for the digital age. Our findings suggest an urgent need to address the regulatory void surrounding online forms of gambling and the promotion of gambling products. This underlines the importance of a public health approach to protect against an increase in gambling-related harms.

Teasing Apart Impacts of Human Activity and Regional Drought on Madagascar’s Large Vertebrate Fauna: Insights From New Excavations at Tsimanampesotse and Antsirafaly

Madagascar experienced a major faunal turnover near the end of the first millenium CE that particularly affected terrestrial, large-bodied vertebrate species. Teasing apart the relative impacts of people and climate on this event requires a focus on regional records with good chronological control. These records may document coeval changes in rainfall, faunal composition, and human activities. Here we present new paleontological and paleoclimatological data from southwestern Madagascar, the driest part of the island today. We collected over 1500 subfossil bones from deposits at a coastal site called Antsirafaly and from both flooded and dry cave deposits at Tsimanampesotse National Park. We built a chronology of Late Holocene changes in faunal assemblages based on 65 radiocarbon-dated specimens and subfossil associations. We collected stalagmites primarily within Tsimanampesotse but also at two additional locations in southern Madagascar. These provided information regarding hydroclimate variability over the past 120,000 years. Prior research has supported a primary role for drought (rather than humans) in triggering faunal turnover at Tsimanampesotse. This is based on evidence of: (1) a large freshwater ecosystem west of what is now the hypersaline Lake Tsimanampesotse, which supported freshwater mollusks and waterfowl (including animals that could not survive on resources offered by the hypersaline lake today); (2) abundant now-extinct terrestrial vertebrates; (3) regional decline or disappearance of certain tree species; and (4) scant local human presence. Our new data allow us to document the hydroclimate of the subarid southwest during the Holocene, as well as shifts in faunal composition (including local extirpations, large-vertebrate population collapse, and the appearance of introduced species). These records affirm that climate alone cannot have produced the observed vertebrate turnover in the southwest. Human activity, including the introduction of cattle, as well as associated changes in habitat exploitation, also played an important role.

Increasing Pleistocene permafrost persistence and carbon cycle conundrums inferred from Canadian speleothems

Permafrost carbon represents a potentially powerful amplifier of climate change, but little is known about permafrost sensitivity and associated carbon cycling during past warm intervals. We reconstruct permafrost history in western Canada during Pleistocene interglacials from 130 uranium-thorium ages on 72 speleothems, cave deposits that only accumulate with deep ground thaw. We infer that permafrost thaw extended to the high Arctic during one or more periods between ~1.5 million and 0.5 million years ago but has been limited to the sub-Arctic since 400,000 years ago. Our Canadian speleothem growth history closely parallels an analogous reconstruction from Siberia, suggesting that this shift toward more stable permafrost across the Pleistocene may have been Arctic-wide. In contrast, interglacial greenhouse gas concentrations were relatively stable throughout the Pleistocene, suggesting that either permafrost thaw did not trigger substantial carbon release to the atmosphere or it was offset by carbon uptake elsewhere on glacial-interglacial time scales.

Cryogenic cave carbonate and implications for thawing permafrost at Winter Wonderland Cave, Utah, USA

Winter Wonderland Cave contains perennial ice associated with two types of cryogenic cave carbonate (CCC) formed during the freezing of water. CCC_fine is characterized by relatively high δ¹³C values, whereas CCC_coarse exhibits notably low δ¹⁸O values indicating precipitation under (semi)closed-system conditions in a pool of residual water beneath an ice lid. Previous work has concluded that CCC_coarse forms during permafrost thaw, making the presence of this precipitate a valuable indicator of past cryospheric change. Available geochronologic evidence indicates that CCC formation in this cave is a Late Holocene or contemporary process, and field observations suggest that the cave thermal regime recently changed in a manner that permits the ingress of liquid water. This is the first documented occurence of CCC_coarse in the Western Hemisphere and one of only a few locations where these minerals have been found in association with ice. Winter Wonderland Cave is a natural laboratory for studying CCC genesis.

Anthropogenic Decline of African Dust: Insights From the Holocene Records and Beyond

African dust exhibits strong variability on a range of time scales. Here we show that the interhemispheric contrast in Atlantic SST (ICAS) drives African dust variability at decadal to millennial timescales, and the strong anthropogenic increase of the ICAS in the future will decrease African dust loading to a level never seen during the Holocene. We provide a physical framework to understand the relationship between the ICAS and African dust activity: positive ICAS anomalies push the Intertropical Convergence Zone (ITCZ) northward and decrease surface wind speed over African dust source regions, which reduces dust emission and transport. It provides a unified framework for and is consistent with relationships in the literature. We find strong observational and proxy-record support for the ICAS-ITCZ-dust relationship during the past 160 and 17,000 years. Model-projected anthropogenic increase of the ICAS will reduce African dust by as much as 60%, which has broad consequences.

Andean drought and glacial retreat tied to Greenland warming during the last glacial period

Abrupt warming events recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials are linked to changes in tropical circulation during the last glacial cycle. Corresponding variations in South American summer monsoon (SASM) strength are documented, most commonly, in isotopic records from speleothems, but less is known about how these changes affected precipitation and Andean glacier mass balance. Here we present a sediment record spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes that has sufficient chronologic precision to document abrupt climatic events on a centennial-millennial time scale. DO events involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake. Our results reveal the magnitude of the hydroclimatic disruptions in the highest reaches of the Amazon Basin that were caused by a weakening of the SASM during abrupt arctic warming. Accentuated warming in the Arctic could lead to significant reductions in the precipitation-evaporation balance of the southern tropical Andes with deleterious effects on this densely populated region of South America.

How the abrupt warming events recorded in Greenland ice cores during the last glacial cycle have influenced the tropical climate is not well known. Here the authors present new lake sediment data from the Peruvian Andes that shows that these events resulted in rapid glacier retreat and large reductions in lake level.

Corporations in global health: an investigation of food industry political activity at the WHO

Background

With over ten million annual deaths now attributable to unhealthy diets, there is an urgent need for action, yet, political progress is too slow. Policy interference by major corporations is well documented in the area of tobacco control. Evidence shows similar behaviours by the food industry at country level, but global-level policymaking remains under-researched. Thus, this study explores how food industry actors seek to influence dietary non-communicable disease (NCD) policy at the World Health Organization (WHO).

Methods

We identified relevant industry documents from the Food Industry Documents Library and academic articles, using these initial findings and an existing model of corporate political activity as the basis for sixteen key informant interviews. Key industry strategies were identified in an iterative process of qualitative thematic coding. Additionally, food industry responses to five WHO consultations on NCD policy and governance (2015-2018) were analysed to explore how evidence was used.

Results

Food industry actors have substantial access to the WHO through formal routes. These interactions largely take place through business associations rather than individual companies, owing at least partly to the agency's own guidelines. Food industry actors can also access global-level policymaking indirectly, for example, by lobbying national political actors to adopt favourable positions in member state-led WHO decision-making, or by co-opting civil society. In consultation responses, the majority of evidence cited by commercial actors was either industry-linked or industry-funded, and less than half was peer-reviewed.

Conclusions

Focusing on the WHO's NCD agenda, we provide new insights into the ways food industry actors seek to influence global public health policy. Although their political behaviour bears similarities with that of the tobacco industry, multinational food companies are, in contrast, widely treated as part of the solution.

Key messages

By mapping how food industry actors seek to shape WHO policy, this research adds to evidence from national contexts and highlights a need for better safeguards across levels of governance. While the tobacco industry is prohibited from engagement with global NCD policy, multinational food corporations enjoy significant access and legitimacy, despite similarities in political behaviour.

On the normalisation of online sports gambling among young adult men in the UK: a public health perspective

OBJECTIVES

Online sports gambling has become an increasingly popular feature of male youth culture and fandom in recent decades. Fuelled by advances in mobile app technologies and the liberalisation of state regulations on advertising, this 'gamblification' of sport has given rise to a global industry promoting gambling as a knowledge-based, risk-free leisure activity. This study examined how the growth of online sports gambling has impacted on gambling behaviours among young adult men in the UK and how it may pose new risks concerning the normalisation of gambling behaviours.

STUDY DESIGN

The study used a multiphased qualitative research design.

METHODS

The study was conducted with 32 adult men (aged 18-35 years) across two sites, Derry, Northern Ireland, and Bristol, England. It comprised three phases of data collection: participatory focus groups, a 30-day gambling diary and semistructured interviews.

RESULTS

Four main themes emerged. First, data suggest that gambling has become a normalised aspect of sports fandom for male youth demographics, many of whom view the casual wagering of money as vital to their enjoyment of sport. Second, the perceived 'facelessness' of sports gambling platforms via mobile app technologies was reported to increase inclination to engage in sports betting. Third, 'free bet' incentives and in-play promotions play a significant role as a mechanism of inducement towards sports gambling practices. Fourth was the potential role of online sports gambling as a gateway to gambling-related harms, including financial precarity, indebtedness, mortgage defaults, family breakdown, loss of employment and mental health struggles.

CONCLUSION

Online sports gambling has significant public health implications, particularly for male youth demographics. Policymakers in the UK should consider stronger regulation of gambling-related advertising and sponsorship in sport, independent risk assessments of sports gambling products and a commitment to safeguarding youth demographics from gambling-related harm in a digital age.

Glacial-Interglacial Precipitation Changes

Glacial-interglacial cycles have constituted a primary mode of climate variability over the last 2.6 million years of Earth's history. While glacial periods cannot be seen simply as a reverse analogue of future warming, they offer an opportunity to test our understanding of the response of precipitation patterns to a much wider range of conditions than we have been able to directly observe. This review explores key features of precipitation patterns associated with glacial climates, which include drying in large regions of the tropics and wetter conditions in substantial parts of the subtropics and midlatitudes. I describe the evidence for these changes and examine the potential causes of hydrological changes during glacial periods. Central themes that emerge include the importance of atmospheric circulation changes in determining glacial-interglacial precipitation changes at the regional scale, the need to take into account climatic factors beyond local precipitation amount when interpreting proxy data, and the role of glacial conditions in suppressing the strength of Northern Hemisphere monsoon systems.

A new interpretation of Madagascar's megafaunal decline: The "Subsistence Shift Hypothesis"

Fundamental disagreements remain regarding the relative importance of climate change and human activities as triggers for Madagascar's Holocene megafaunal extinction. We use stable isotope data from stalagmites from northwest Madagascar coupled with radiocarbon and butchery records from subfossil bones across the island to investigate relationships between megafaunal decline, climate change, and habitat modification. Archaeological and genetic evidence support human presence by 2000 years Before Common Era (BCE). Megafaunal decline was at first slow; it hastened at ∼700 Common Era (CE) and peaked between 750 and 850 CE, just before a dramatic vegetation transformation in the northwest that resulted in the replacement of C₃ woodland habitat with C₄ grasslands, during a period of heightened monsoonal activity. Cut and chop marks on subfossil lemur bones reveal a shift in primary hunting targets from larger, now-extinct species prior to ∼900 CE, to smaller, still-extant species afterwards. By 1050 CE, megafaunal populations had essentially collapsed. Neither the rapid megafaunal decline beginning ∼700 CE, nor the dramatic vegetation transformation in the northwest beginning ∼890 CE, was influenced by aridification. However, both roughly coincide with a major transition in human subsistence on the island from hunting/foraging to herding/farming. We offer a new hypothesis, which we call the "Subsistence Shift Hypothesis," to explain megafaunal decline and extinction in Madagascar. This hypothesis acknowledges the importance of wild-animal hunting by early hunter/foragers, but more critically highlights negative impacts of the shift from hunting/foraging to herding/farming, settlement by new immigrant groups, and the concomitant expansion of the island's human population. The interval between 700 and 900 CE, when the pace of megafaunal decline quickened and peaked, coincided with this economic transition. While early megafaunal decline through hunting may have helped to trigger the transition, there is strong evidence that the economic shift itself hastened the crash of megafaunal populations.

Monsoon-driven Saharan dust variability over the past 240,000 years

Reconstructions of past Saharan dust deposition in marine sediments provide foundational records of North African climate over time scales of 10³ to 10⁶ years. Previous dust records show primarily glacial-interglacial variability in the Pleistocene, in contrast to other monsoon records showing strong precessional variability. Here, we present the first Saharan dust record spanning multiple glacial cycles obtained using ²³⁰Th normalization, an improved method of calculating fluxes. Contrary to previous data, our record from the West African margin demonstrates high correlation with summer insolation and limited glacial-interglacial changes, indicating coherent variability in the African monsoon belt throughout the late Pleistocene. Our results demonstrate that low-latitude Saharan dust emissions do not vary synchronously with high- and mid-latitude dust emissions, and they call into question the use of existing Plio-Pleistocene dust records to investigate links between climate and hominid evolution.

Western U.S. lake expansions during Heinrich stadials linked to Pacific Hadley circulation

Lake and cave records show that winter precipitation in the southwestern United States increased substantially during millennial-scale periods of Northern Hemisphere winter cooling known as Heinrich stadials. However, previous work has not produced a clear picture of the atmospheric circulation changes driving these precipitation increases. Here, we combine data with model simulations to show that maximum winter precipitation anomalies were related to an intensified subtropical jet and a deepened, southeastward-shifted Aleutian Low, which together increased atmospheric river-like transport of subtropical moisture into the western United States. The jet and Aleutian Low changes are tied to the southward displacement of the intertropical convergence zone and the accompanying intensification of the Hadley circulation in the central Pacific. These results refine our understanding of atmospheric changes accompanying Heinrich stadials and highlight the need for accurate representations of tropical-extratropical teleconnections in simulations of past and future precipitation changes in the region.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks

Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exist documenting past changes in long-range dust transport. This data gap limits investigations of the role of Saharan dust in past climate change, in particular during the mid-Holocene, when climate models consistently underestimate the intensification of the West African monsoon documented by paleorecords. We present reconstructions of African dust deposition in sediments from the Bahamas and the tropical North Atlantic spanning the last 23,000 years. Both sites show early and mid-Holocene dust fluxes 40 to 50% lower than recent values and maximum dust fluxes during the deglaciation, demonstrating agreement with records from the northwest African margin. These quantitative estimates of trans-Atlantic dust transport offer important constraints on past changes in dust-related radiative and biogeochemical impacts. Using idealized climate model experiments to investigate the response to reductions in Saharan dust's radiative forcing over the tropical North Atlantic, we find that small (0.15°C) dust-related increases in regional sea surface temperatures are sufficient to cause significant northward shifts in the Atlantic Intertropical Convergence Zone, increased precipitation in the western Sahel and Sahara, and reductions in easterly and northeasterly winds over dust source regions. Our results suggest that the amplifying feedback of dust on sea surface temperatures and regional climate may be significant and that accurate simulation of dust's radiative effects is likely essential to improving model representations of past and future precipitation variations in North Africa.

Vitamin D-binding protein levels do not influence the effect of vitamin D repletion on serum PTH and calcium: data from a randomized, controlled trial

CONTEXT

Vitamin D deficiency, defined by the total serum 25-hydroxyvitamin D [25(OH)D] level, is common and more prevalent among Blacks than whites. Vitamin D-binding protein (DBP) levels vary with race and may modulate "bioavailable" levels of 25(OH)D.

OBJECTIVE

To determine the effect of DBP levels on the functional response to vitamin D.

SETTING AND DESIGN

A randomized, placebo-controlled trial of vitamin D repletion for 2 mo, which took place at an outpatient research unit. Participants included 150 vitamin D-deficient (25(OH)D <20 ng/mL) adults. Participants were randomly assigned to receive either 50,000 IU of vitamin D3 or placebo weekly for 8 weeks. This is a post-hoc analysis using DBP, 25(OH)D, PTH, and calcium levels.

RESULTS

Blacks had lower total 25(OH)D (12 vs 15 ng/mL, P < .001) and DBP levels (119 vs 234 μg/mL, P < .001) than non-Blacks. DBP levels were similar before and after vitamin D3 or placebo treatment (r = 0.98, P < .001). Baseline total 25(OH)D levels were a significant determinant of baseline PTH levels (P < .001). The change in total 25(OH)D was associated with the change in PTH (P < 0.001) and calcium levels (P < .05). In contrast, DBP levels were not a determinant of baseline PTH (P = .57) nor significantly related to changes in either PTH (P = .53) or calcium levels (P = .88).

CONCLUSIONS

DBP levels are stable in Blacks and non-Blacks, and do not change with correction of vitamin D deficiency. Even for individuals with total 25(OH)D levels < 20 ng/mL, Blacks have significantly lower DBP levels than non-Blacks. However, within this range of total 25(OH)D, DBP levels do not influence the effect of vitamin D repletion on PTH or calcium levels.

Mast cells: a pivotal role in pulmonary fibrosis

Pulmonary fibrosis is characterized by an inflammatory response that includes macrophages, neutrophils, lymphocytes, and mast cells. The purpose of this study was to evaluate whether mast cells play a role in initiating pulmonary fibrosis. Pulmonary fibrosis was induced with bleomycin in mast-cell-deficient WBB6F1-W/W(v) (MCD) mice and their congenic controls (WBB6F1-(+)/(+)). Mast cell deficiency protected against bleomycin-induced pulmonary fibrosis, but protection was reversed with the re-introduction of mast cells to the lungs of MCD mice. Two mast cell mediators were identified as fibrogenic: histamine and renin, via angiotensin (ANG II). Both human and rat lung fibroblasts express the histamine H1 and ANG II AT1 receptor subtypes and when activated, they promote proliferation, transforming growth factor β1 secretion, and collagen synthesis. Mast cells appear to be critical to pulmonary fibrosis. Therapeutic blockade of mast cell degranulation and/or histamine and ANG II receptors should attenuate pulmonary fibrosis.

Visual cycle modulation in neurovascular retinopathy

Rats with oxygen-induced retinopathy (OIR) model the pediatric retinal disease retinopathy of prematurity (ROP). Recent findings in OIR rats imply a causal role for the rods in the ROP disease process, although only experimental manipulation of rod function can establish this role conclusively. Accordingly, a visual cycle modulator (VCM) - with no known direct effect on retinal vasculature - was administered to "50/10 model" OIR Sprague-Dawley rats to test the hypotheses that it would 1) alter rod function and 2) consequently alter vascular outcome. Four litters of pups (N=46) were studied. For two weeks, beginning on postnatal day (P) 7, the first and fourth litters were administered 6 mg kg(-1) N-retinylacetamide (the VCM) intraperitoneally; the second and third litters received vehicle (DMSO) alone. Following a longitudinal design, retinal function was assessed by electroretinography (ERG) and the status of the retinal vessels was monitored using computerized fundus photograph analysis. Rod photoreceptor and post-receptor response amplitudes were significantly higher in VCM-treated than in vehicle-treated rats; deactivation of phototransduction was also significantly more rapid. Notably, the arterioles of VCM-treated rats showed significantly greater recovery from OIR. Presuming that the VCM did not directly affect the retinal vessels, a causal role for the neural retina - particularly the rod photoreceptors - in OIR was confirmed. There was no evidence of negative alteration of photoreceptor function consequent to VCM treatment. This finding implicates the rods as a possible therapeutic target in neurovascular diseases such as ROP.

Covariant glacial-interglacial dust fluxes in the equatorial Pacific and Antarctica

Dust plays a critical role in Earth's climate system and serves as a natural source of iron and other micronutrients to remote regions of the ocean. We have generated records of dust deposition over the past 500,000 years at three sites spanning the breadth of the equatorial Pacific Ocean. Equatorial Pacific dust fluxes are highly correlated with global ice volume and with dust fluxes to Antarctica, which suggests that dust generation in interhemispheric source regions exhibited a common response to climate change over late-Pleistocene glacial cycles. Our results provide quantitative constraints on the variability of aeolian iron supply to the equatorial Pacific Ocean and, more generally, on the potential contribution of dust to past climate change and to related changes in biogeochemical cycles.

Advanced glycation end-products and methionine sulphoxide in skin collagen of patients with type 1 diabetes

AIMS/HYPOTHESIS

We determined whether oxidative damage in collagen is increased in (1) patients with diabetes; (2) patients with diabetic complications; and (3) subjects from the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study, with comparison of subjects from the former standard vs intensive treatment groups 4 years after DCCT completion.

SUBJECTS, MATERIALS AND METHODS

We quantified the early glycation product fructose-lysine, the two AGEs N (epsilon)-(carboxymethyl)lysine (CML) and pentosidine, and the oxidised amino acid methionine sulphoxide (MetSO) in skin collagen from 96 patients with type 1 diabetes (taken from three groups: DCCT/EDIC patients and clinic patients from South Carolina and Scotland) and from 78 healthy subjects.

RESULTS

Fructose-lysine was increased in diabetic patients (p<0.0001), both with or without complications (p<0.0001). Controlling for HbA(1c), rates of accumulation of AGEs were higher in diabetic patients than control subjects, regardless of whether the former had complications (CML and pentosidine given as log(e)[pentosidine]) or not (CML only) (all p<0.0001). MetSO (log(e)[MetSO]) also accumulated more rapidly in diabetic patients with complications than in controls (p<0.0001), but rates were similar in patients without complications and controls. For all three products, rates of accumulation with age were significantly higher in diabetic patients with complications than in those without (all p<0.0001). At 4 years after the end of the DCCT, no differences were found between the previous DCCT management groups for fructose-lysine, AGEs or MetSO.

CONCLUSIONS/INTERPRETATION

The findings suggest that in type 1 diabetic patients enhanced oxidative damage to collagen is associated with the presence of vascular complications.

Nuclear magnetic resonance-determined lipoprotein subclass profile in the DCCT/EDIC cohort: associations with carotid intima-media thickness

AIMS

To relate nuclear magnetic resonance lipoprotein subclass profiles (NMR-LSP) and other lipoprotein-related factors with carotid intima-media thickness (IMT) in Type 1 diabetes.

METHODS

Lipoprotein-related factors were determined in sera (obtained in 1997-1999) from 428 female [age 39 +/- 7 years (mean +/- SD)] and 540 male (age 40 +/- 7 years) Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) participants. NMR quantifies chylomicrons, three very low-density lipoprotein (VLDL) subclasses, intermediate density lipoprotein (IDL), three low-density lipoprotein (LDL) subclasses, two high-density lipoprotein (HDL) subclasses, mean VLDL, LDL and HDL size, and LDL particle concentration. Conventional lipids, ApoA1, ApoB and Lp(a) and in vitro LDL oxidizibility were also measured. IMT was determined (in 1994-1995) using high-resolution B-mode ultrasound. Relationships between IMT and lipoproteins were analysed by multiple linear regression, controlling for age, diabetes-related factors, and cardiovascular disease (CVD) risk factors.

RESULTS

IMT associations with lipoproteins were stronger for the internal than the common carotid artery, predominantly involving LDL. Internal carotid IMT was positively (P < 0.05) associated with NMR-based LDL subclasses and particle concentration, and with conventional LDL-cholesterol and ApoB in both genders. Common carotid IMT was associated, in men only, with large VLDL, IDL, conventional LDL cholesterol and ApoB.

CONCLUSIONS

NMR-LSP reveals significant associations with carotid IMT in Type 1 diabetic patients, even 4 years after IMT measurement. NMR-LSP may aid early identification of high-risk diabetic patients and facilitate monitoring of interventions. Longer DCCT/EDIC cohort follow-up will yield CVD events and IMT progression, permitting more accurate assessment of pre-morbid lipoprotein profiles as determinants of cardiovascular risk in Type 1 diabetes.

Psychiatric nurses' perspectives of spirituality and spiritual needs during an amalgamation

The purpose of this study was to explore the meaning of spirituality and how the spiritual needs of psychiatric nurses could be supported at work during a hospital amalgamation. Forty-six nurses completed the General Information Questionnaire and described the meaning of spirituality and how their spiritual needs could be supported. Data were analysed by the double-coding qualitative method. The themes identified for the meaning of spirituality included: being hopeful, having belief/belief systems, maintaining relatedness/connectedness and the expression of spirituality. The major themes identified to support nursing staffs' spiritual needs at work included communication, offering hope, being valued and support from spiritual sources. Nurses expressed the importance of spirituality in their lives and the need for spiritual support at work. Data for addressing staff spiritual needs are reported; however, further studies are needed to understand the spiritual needs of nursing staff at work during hospital amalgamations.

Lack of association between androgen receptor polymorphisms and bone mineral density or physical function in older men

Individuals whose androgen receptors have short polyglutamine tracts (resulting from CAG repeats) may have greater receptor signaling activity of the androgen receptor. We evaluated the association between bone mineral density (BMD) and CAG repeats in 91 older men with normal (control) and low femoral neck (EN) BMD (OP) or a history of femoral fracture (FX). Bioavailable testosterone (BioT) and physical performance, including composite score (EPESE) and physical activity (PASE), were also measured. Comparing FX, OP, and control subjects, we observed BMD Tscores of -2.16 +/- 1.08, -2.26 +/- 0.74, and -0.20 +/- 0.40 (p < 0.001); CAG repeat lengths of 21.9 +/- 2.7, 22.5 +/- 2.4, and 22.3 +/- 2.9 (p = 0.63); BioT levels of 2.29 +/- 1.25, 2.19 +/- 1.11, and 3.99 +/- 1.25 nmol/L (p < 0.001); EPESE scores of 8.0 +/- 3.0, 9.7 +/- 2.0, and 11.3 +/- 0.9 (p < 0.001); and PASE scores of 91 +/- 66, 122 +/- 66, and 200 +/- 55 (p < 0.001), respectively. There were no significant correlations between CAG repeats and BioT or physical performance. Men with osteoporosis or fracture had lower BioT, physical performance, and physical activity than controls. This study found no association between CA G repeats and FN BMD in older men with normal or low BMD or FX.

Engineering inhibitors highly selective for the S1 sites of Ser190 trypsin-like serine protease drug targets

BACKGROUND

Involved or implicated in a wide spectrum of diseases, trypsin-like serine proteases comprise well studied drug targets and anti-targets that can be subdivided into two major classes. In one class there is a serine at position 190 at the S1 site, as in urokinase type plasminogen activator (urokinase or uPA) and factor VIIa, and in the other there is an alanine at 190, as in tissue type plasminogen activator (tPA) and factor Xa. A hydrogen bond unique to Ser190 protease-arylamidine complexes between O gamma(Ser190) and the inhibitor amidine confers an intrinsic preference for such inhibitors toward Ser190 proteases over Ala190 counterparts.

RESULTS

Based on the structural differences between the S1 sites of Ser190 and Ala190 protease-arylamidine complexes, we amplified the selectivity of amidine inhibitors toward uPA and against tPA, by factors as high as 220-fold, by incorporating a halo group ortho to the amidine of a lead inhibitor scaffold. Comparison of K(i) values of such halo-substituted and parent inhibitors toward a panel of Ser190 and Ala190 proteases demonstrates pronounced selectivity of the halo analogs for Ser190 proteases over Ala190 counterparts. Crystal structures of Ser190 proteases, uPA and trypsin, and of an Ala190 counterpart, thrombin, bound by a set of ortho (halo, amidino) aryl inhibitors and of non-halo parents reveal the structural basis of the exquisite selectivity and validate the design principle.

CONCLUSIONS

Remarkable selectivity enhancements of exceptionally small inhibitors are achieved toward the uPA target over the highly similar tPA anti-target through a single atom substitution on an otherwise relatively non-selective scaffold. Overall selectivities for uPA over tPA as high as 980-fold at physiological pH were realized. The increase in selectivity results from the displacement of a single bound water molecule common to the S1 site of both the uPA target and the tPA anti-target because of the ensuing deficit in hydrogen bonding of the arylamidine inhibitor when bound in the Ala190 protease anti-target.

Serum distribution of lipoprotein(a) in African Americans and Nigerians: potential evidence for a genotype-environmental effect

Differences in lipoprotein(a) [Lp(a)] levels across populations have been described and blacks are known to have higher Lp(a) values compared to whites. However, environmental factors which influence Lp(a) levels have been difficult to identify. We took advantage of the large environmental contrast which exists against a common genetic background between U.S. and Nigerian blacks to examine the relationship between Lp(a) and apolipoprotein(a) magnitude of apo(a) isoforms. Although the distribution of Lp(a) and apo(a) isoforms was nearly Gaussian in both populations, mean serum Lp(a) values were significantly higher in the United States than in Nigeria (20.5 vs. 12.7 mg/dl; P = 0.0001) and U.S. blacks had a higher frequency of the large molecular weight isoforms compared to Nigerians. Similar trends in the relationship between apo(a) isoform and Lp(a) concentration were seen in both populations; however, the magnitude of the effect was different. Compared to the Nigerians, U.S. blacks had significantly higher mean Lp(a) values for the same apo(a) isoform. The association of Lp(a) with low density lipoprotein-cholesterol (LDL-C) level was not significant after correcting for the contribution of Lp(a) cholesterol to LDL-C in both populations. Surprisingly, the association between Lp(a) and total-C remained significant (r = 0.20, P = 0.04) after similar correction for the contribution of Lp(a) cholesterol in the U.S. sample. Understanding the relationship between other factors including lifestyle characteristics capable of influencing total-C may help explain the unusually high Lp(a) level observed in this U.S. population.

Reliability and validity of the CANDID--a needs assessment instrument for adults with learning disabilities and mental health problems

BACKGROUND

People with learning disabilities and mental health problems have complex needs. Care should be provided according to need.

AIM

To develop a standardised needs-assessment instrument for adults with learning disabilities and mental health problems.

METHOD

The Camberwell Assessment of Need for Adults with Developmental and Intellectual Disabilities (CANDID) was developed by modifying the Camberwell Assessment of Need (CAN). Concurrent validity was tested using the Global Assessment of Functioning (GAF) and the Disability Assessment Schedule (DAS). Test-retest and interrater reliability were investigated using 40 adults with learning disabilities and mental health problems.

RESULTS

CANDID scores were significantly correlated with both DAS (P < 0.05) and GAF scores (P < 0.01). Correlation coefficients for interrater reliability were 0.93 (user), 0.90 (career), and 0.97 (staff ratings); for test-retest reliability they were 0.71, 0.69 and 0.86 respectively. Mean interview duration was less than 30 minutes.

CONCLUSIONS

The CANDID is a brief, valid and reliable needs assessment instrument for adults with learning disabilities and mental health problems.

A pilot study of cervical screening in an inner city area--lessons for a national programme

The objectives of this study were to examine aspects of organization of a proposed national screening programme based in general practice. The target population of women aged 25-59 years and their general practitioners (GPs), in a defined inner city area, was identified from a population register of persons eligible for free medical services; a computerized system was developed for invitations and record linkage of cytology results. Smears were examined in one laboratory and follow up of women with abnormal smears was undertaken by one gynaecologist. A random sample of non-responders was surveyed by questionnaire. Response following two invitations was only 20%. Practices with male doctors only had significantly lower response rates (P < 0.001) than those with a female doctor/nurse. A survey of non-responders showed that over 20% of addresses were incorrect and 16% of those interviewed were ineligible for smear tests. A preference for a female to undertake smears was expressed by 67%, and 77% believed that the purpose of the cervical smear was to detect cancer. An accurate population register, health promotion, support for GP practices, provision of alternative venues for smear tests, development of computer systems, accurate data entry and fail-safe follow up are aspects of a cervical screening service which must be addressed prior to setting up a national service.

Relation between body mass index and body fat in black population samples from Nigeria, Jamaica, and the United States

Body mass index (BMI) is the most commonly used measure of obesity. Recently, some investigators have advocated direct measurement of adiposity rather than use of the BMI. This study was undertaken to determine the ability of BMI to predict body fat levels in three populations of West African heritage living in different environments. A total of 1,054 black men and women were examined in Nigeria, Jamaica, and the United States during 1994 and 1995. A standardized protocol was used to measure height, weight, waist and hip circumferences, and blood pressure at all sites; percentage of body fat was estimated using bioelectrical impedance analysis. Percentage of body fat and BMI were highly correlated within site- and sex-specific groups, and the resulting r2 ranged from 0.61 to 0.85. The relation was quadratic in all groups except Nigerian men, in whom it was linear. The regression coefficients were similar across sites, yet the mean body fat levels differed significantly (p < 0.001) as estimated by the intercept, making intersite comparison difficult. Compared with BMI, percentage of body fat was not a better predictor of blood pressure or waist or hip circumference.

The prevalence of hypertension in seven populations of west African origin

OBJECTIVES

This study was undertaken to describe the distribution of blood pressures, hypertension prevalence, and associated risk factors among seven populations of West African origin.

METHODS

The rates of hypertension in West Africa (Nigeria and Cameroon), the Caribbean (Jamaica, St. Lucia, Barbados), and the United States (metropolitan Chicago, Illinois) were compared on the basis of a highly standardized collaborative protocol. After researchers were given central training in survey methods, population-based samples of 800 to 2500 adults over the age of 25 were examined in seven sites, yielding a total sample of 10014.

RESULTS

A consistent gradient of hypertension prevalence was observed, rising from 16% in West Africa to 26% in the Caribbean and 33% in the United States. Mean blood pressures were similar among persons aged 25 to 34, while the increase in hypertension prevalence with age was twice as steep in the United States as in Africa. Environmental factors, most notably obesity and the intake of sodium and potassium, varied consistently with disease prevalence across regions.

CONCLUSION

The findings demonstrate the determining role of social conditions in the evolution of hypertension risk in these populations.

Simultaneous monitoring of heart rate and motion to assess energy expenditure

Measurement of energy expenditure in free-living individuals represents a methodologic challenge in epidemiologic research. Heart rate monitors, while closely tied to energy expenditure at high levels of energy output, provide much less predictive power at low levels; however, measurement of motion may improve the predictive ability. This study was undertaken to determine the usefulness of simultaneously monitoring heart rate and motion for the estimation of energy expenditure. Ten subjects were studied during simulated activities of daily living (ADLC) and submaximal treadmill tests. Compared to direct measurement, the motion sensor predicted oxygen consumption poorly (r2 = 0.53) for both tests. Heart rate measured simultaneously yielded an r2 of 0.81 for ADLC and 0.90 for the treadmill. Addition of motion data increased the r2 value for the ADLC for all but one individual and increased the group mean from 0.81 to 0.86. This improvement was not observed for the treadmill, confirming the hypothesis that the principle value of monitoring motion occurs at lower heart rates.

Patterns of comorbidity and mortality risk in blacks and whites

Comorbidity, the co-existence of multiple chronic conditions in a single individual, has been shown to modify the prognosis of disease states. To estimate disease burdens within and among racial subpopulations of the United States, we examined cross-sectional patterns of comorbidity and their impact on survival using data from the NHANES-1 Epidemiologic Follow-up Study (NHEFS). We considered the occurrence of four cardiovascular conditions: stroke, coronary heart disease, hypertension and diabetes. We summarize the joint occurrence of these four conditions using these different methodologies: the number of conditions occurring in each individual and two summaries that weight the conditions according to their prognostic significance. Using all three methodologies, we found an excess burden of chronic disease in black women as compared with white women. Black men had an excess burden compared to white men for the first two methodologies. However, when we model the relationship of the joint occurrence of the conditions to subsequent mortality, black men and white men are seen to have a similar burden. This similarity of black and white men is due to an interaction between race and prevalent stroke in men that we hypothesize may be due to the small number of black men available for study. Given the apparent conditioning effect of co-existing diseases, it is evident that estimation of disease burdens among groups that differ in terms of health status, in particular among U.S. blacks and whites, requires accounting for the occurrence of multiple chronic diseases. Using either the number of conditions or the prognosis weighted summary, we demonstrated a higher burden of the conditions considered in blacks that in whites in a sample of the U.S. population.

Standardization of blood pressure measurement in an international comparative study

In the context of a collaborative study on the epidemiology of hypertension in populations of West African origin procedures for standardization of the measurement of blood pressure were evaluated. Comparisons of mean levels of blood pressure, which in large part determine prevalence rates, are highly sensitive to differences in technique. While rotating a single field team may be the ideal approach to multisite studies, it is not practical in international collaborative research. Appropriate techniques to standardize multiple teams over a long period of time have not been well developed, however. In the present study 8981 individuals were examined in eight sites in six countries with the standard mercury sphygmomanometer. An evaluation of the effectiveness of central training, site visits, monitoring of digit preference, and the use of an electronic device for internal standardization is described. In all but one of the sites reliability was high and comparable to the observers at the Coordinating Center. Digit preference for the entire set of measurements was limited (frequency of terminal zero = 23.5% for systolic and 28.9% for diastolic readings) and could be shown to have virtually no effect on prevalence rates or correlation estimates. Mean differences among observers within a given site and between sites were small (+/- 0-5 mmHg). While logistically complex, these methods can provide the basis for standardization in international comparative blood pressure surveys.

Identifying obstructive sleep apnea in patients presenting for laser-assisted uvulopalatoplasty

The authors report on a series of 850 patients with snoring who were evaluated for laser-assisted uvulopalatoplasty (LAUP). Stepwise multivariate linear regression was employed to correlate patient symptoms and characteristics to the respiratory disturbance index (RDI). Body mass index, falling asleep while driving, snoring every night, and stopping breathing during sleep were found to correlate strongly with an increasing RDI (variance of 25%). Logistic multivariate linear regression analysis was used to predict the outcome of apnea (RDI>10). This model selected all of the above variables, as well as age, male sex, and the total number of symptoms, as being strong predictors of apnea. A receiver operating characteristic curve was used to describe the ability of this model to predict apnea. The authors conclude that otolaryngologists play an important role in the evaluation of OSAS, especially when a snoring patient may undergo LAUP, and they present an algorithm for the evaluation of such a patient. The authors believe that the clinical assessment, including a thorough history and a complete physical examination, remains extremely important in this evaluation. At present, the authors strongly recommend referral for a PSG if there is any suspicion of OSAS.

Obesity in the Caribbean

People of African origin who live in the Caribbean share a common genetic heritage but live in socioeconomic environments that diverge widely. A cross-cultural study of males and females from Jamaica, St. Lucia and Barbados investigated the prevalence of hypertension and its environmental determinants. Standardized measurement techniques allowed comparable measurements of weight, height, waist and hip circumferences, and blood pressure. The population values for body mass index (BMI), per cent overweight (males BMI > or = 27.8 kg/m2; females BMI > or = 27.3 kg/m2) and per cent obese (males BMI > or = 31.1 kg/m2; females BMI > or = 32.3 kg/m2) are presented. Prevalence of hypertension is based on the age-adjusted total population. The gradient in per capita gross national product in Jamaica, St. Lucia and Barbados parallels the gradient in the proportions of population in those countries who are obese. BMI explained 26% of the variance in blood pressure in females and 13% in males. Obesity is a significant problem in the Caribbean, as it is in many other developing countries, and it is associated with a high prevalence of hypertension, particularly in women.

Obesity in peoples of the African diaspora

People of African descent in the Caribbean and the USA originated from the Bight of Benin in West Africa. Although these populations share a common genetic heritage, they now live under different socioeconomical conditions. Assuming genetic similarity, a cross-cultural examination of these peoples in West Africa, the Caribbean and the USA may attenuate the effect of genetic factors and allow the assessment of environmental contributions to a biological outcome. We carried out an epidemiological survey to determine the prevalence of hypertension and the contribution of risk factors to the variation in blood pressure. We measured the height, weight, waist and hip circumferences, and blood pressure of adults in Nigeria, Cameroon, Jamaica, St. Lucia, Barbados and the USA. In urban populations there was a trend towards increasing weight, height, body mass index, and proportions of those overweight and obese going from West Africa to the USA, with the Caribbean being intermediate. The prevalence of hypertension lay on a similar gradient. Given a common genetic susceptibility, urbanization and western acculturation are therefore associated with increasing hypertension and obesity.