Barry McDonald

Diagnosing painful sacroiliac joints: A validity study of a McKenzie evaluation and sacroiliac provocation tests

Research suggests that clinical examination of the lumbar spine and pelvis is unable to predict the results of diagnostic injections used as reference standards. The purpose of this study was to assess the diagnostic accuracy of a clinical examination in identifying symptomatic and asymptomatic sacroiliac joints using double diagnostic injections as the reference standard. In a blinded concurrent criterion-related validity design study, 48 patients with chronic lumbopelvic pain referred for diagnostic spinal injection procedures were examined using a specific clinical examination and received diagnostic intraarticular sacroiliac joint injections. The centralisation and peripheralisation phenomena were used to identify possible discogenic pain and the results from provocation sacroiliac joint tests were used as part of the clinical reasoning process. Eleven patients had sacroiliac joint pain confirmed by double diagnostic injection. Ten of the 11 sacroiliac joint patients met clinical examination criteria for having sacroiliac joint pain. In the primary subset analysis of 34 patients, sensitivity, specificity and positive likelihood ratio (95% confidence intervals) of the clinical evaluation were 91% (62 to 98), 83% (68 to 96) and 6.97(2.70 to 20.27) respectively. The diagnostic accuracy of the clinical examination and clinical reasoning process was superior to the sacroiliac joint pain provocation tests alone. A specific clinical examination and reasoning process can differentiate between symptomatic and asymptomatic sacroiliac joints

Seasonal variation of nutrient intake in pregnancy: effects on infant measures and possible influence on diseases related to season of birth

Objectives:To determine, firstly, if there was any seasonal effect on nutrient intake during pregnancy and birth measures, secondly, if there was any relationship between maternal nutrient intake and infant birth measures according to season and thirdly, to consider the hypothesis that seasonal change in nutrient intake during pregnancy might affect health in later life of some womens offspring.Design:Pilot study to determine number of days required to characterize group intake followed by a prospective cohort study.Setting:Patients attending a city ante-natal clinic in the lower North Island, New Zealand.Subjects:A total of 214 healthy mostly European pregnant women volunteers, entering the second trimester of pregnancy, of whom 10 miscarried and seven withdrew.Methods:Subjects were visited in months 4 and 7 of pregnancy, and months 2, 6 and 12 after birth. Height, weight and skinfolds were measured and questionnaires to determine personal details administered at these times. Subjects recorded 8 days of weighed diets in both the fourth and seventh month. Health records were used to supply infant measures.Results:Significant (P⩽0.05) seasonal variations in fat, carbohydrate, vitamin C and D, B vitamins, β-carotene, sodium, potassium, calcium, phosphorous, sulfur, sodium, chloride, zinc and selenium intakes were found. No significant ‘main effect’ difference in gestational age, infant birthweight, and head circumference was found with season. However, there were significant interactions (P⩽0.05) for each birth season between birth measures and specific maternal nutrients at months 4 and 7 of pregnancy.Conclusion:The significant seasonal variations in nutrient intake in pregnant women, and significant influence of nutrient intake on birth measures in different seasons, suggests seasonal nutrient variation may also affect fetal development at a cellular level. This supports our hypothesis that the development of conditions related to season of birth, including schizophrenia, multiple sclerosis, type I diabetes and longevity, may be influenced by seasonal variation in nutrient intake during pregnancy.

The association of maternal diet and dietary supplement intake in pregnant New Zealand women with infant birthweight.

Objective:To investigate the association of infant birthweight with maternal diet and supplement intake.Subjects/Methods:Prospective cohort study of 504 European and Polynesian urban and rural pregnant volunteers recruited from northern New Zealand clinics. Subjects were visited in months 4 (mth4) and 7 (mth7) of pregnancy when height, weight and skinfolds were measured, questionnaires to determine personal details administered, and diet assessed by a 24-hour recall and 3-day food record.Results:After adjusting for confounders nutrients accounted for up to 5.0% of the total variance in birthweight. Ethnicity was not a significant confounder. A quadratic relationship existed between birthweight and % total energy (%TE) from carbohydrate, fat and protein, most significantly with carbohydrate energy (P=0.002). Birthweight was greatest (∼3600 g) when carbohydrate %TE was 48%, fat 35% and protein 17%. Birthweight was reduced with high β-carotene intakes (mth4, P=0.009) and with both high retinol and β-carotene intakes in mth4 and 7 (average). Birthweight was positively associated with increasing pantothenic acid/biotin ratios (P=0.011), magnesium (P=0.000) and vitamin D (P=0.015) intakes in mth4; with biotin (P=0.040) and B12 intakes above the RDI (P=0.006) in mth7; and with pantothenic acid intake in mth4&7 (P=0.002). Dietary supplement usage was associated with increased birthweight, most significantly iron supplementation (P=0.006).Conclusion:Birthweight was associated with the %TE from carbohydrate, fat and protein, and with β-carotene, retinol, vitamins D and B12, pantothenic acid, biotin and magnesium intakes and iron supplementation. More research may be required on some dietary recommendations for pregnancy.

Clinical predictors of lumbar provocation discography: a study of clinical predictors of lumbar provocation discography

Discography is the only available method of directly challenging the discs for pain sensitivity. However, it is invasive, expensive and there is a debate about its clinical value. There is a need to identify clinical signs that may indicate the need for a discography examination. Pain centralization (retreat of referred pain to towards the spinal midline) has been associated with positive discography and possesses specificity between 80 and 100% depending on levels of disablement and psychosocial distress. Less than half of positive discography patients reports centralization and there is a need to identify other potentially valuable predictors. This study estimated the diagnostic accuracy of clinical variables in relation to provocation discography. In a blinded, prospective reference standard design in a private interventional radiology clinic, chronic low back patients received a detailed clinical examination followed by discography. Patients were typically disabled with high levels of psychosocial distress. Logistic regression modelling identified potentially useful clinical variables, and sensitivity, specificity and likelihood ratios were calculated for promising specific variables and combinations of variables. Of 118 consecutive discography cases, 107 had unconfounded data on discography results. History of persistent pain between acute episodes, a significant loss of extension and a subjective report of ‘vulnerability’ in what is termed as the ‘neutral zone’ had specificities of 83–92% and likelihood ratios between 2.0 and 4.1. Two combinations of variables were highly specific to positive discography, but no suitable screening test useful for ruling out positive discography was established. Three clinical variables have modest predictive power in relation to lumbar discography results and two combinations of variables were highly specific to positive discography.

Activity levels in pregnant New Zealand women: relationship with socioeconomic factors, well-being, anthropometric measures, and birth outcome.

Activity during pregnancy has health implications for mother and child. The aim of this prospective cohort study was to examine changes in activity levels during pregnancy; the influence of socioeconomic factors and well-being on activity, and the influence of activity on maternal anthropometric measures and birth outcome. Twenty-four hour activity diaries were collected for 3 d in months 4 and 7 of pregnancy in 197 volunteers. Anthropometric measures and questionnaires to determine personal details were collected at these times and 2 months post-partum. Health records were used to supply infant measures. The time spent on each activity category was calculated, and used to calculate overall daily metabolic equivalents (METs). Low socioeconomic (SES) group 24 h activity levels were significantly higher than for high SES or welfare groups (p = 0.013). Activity declined throughout pregnancy in all groups (p = 0.002). Women with children had higher 24 h activity, spending 41% more time walking and (or) on housework than nulliparous women (p = 0.013). Reduced well-being was associated with lower levels of activity. Sleep and lying down time influenced 2 month post-partum body mass (upper quartile gained 2.54 kg, lower quartile lost 0.24 kg, p < 0.001). Mean infant gestational age increased with increasing 24 h activity (p = 0.047). No infants were born prematurely to mothers who spent more than 190 min/d walking or doing housework activities in month 4. Probability of infant admission to the neonatal intensive care unit (NICU) declined with time spent walking or doing housework in month 4 (p = 0.007). Mean (SE) birth weight was 3883 (+/-165) g in the 10% of women spending less than 530 min sleeping or lying down per day, compared with 3413 (+/-104) g in the 10% of women spending 725 min or more sleeping or lying down. Socioeconomic factors were therefore important influences on activity levels during pregnancy. Inactivity, especially in early pregnancy, was associated with more maternal weight retention at 2 months post-partum and a greater probability of admission to NICU and premature delivery.

Multivariate analysis of the long-term results of coronary artery bypass grafting performed during 1976 and 1977

The results of 492 consecutive coronary artery bypass grafting operations performed for angina in the 2-year period from 1976 to 1977 were evaluated 77 months after surgery. Follow-up was complete in 99%. In 80% of patients angina severity was New York Heart Association functional classes III or IV. An ejection fraction of less than 50% and left ventricular end-diastolic pressure of more than 15 mm Hg were each present in one-third of patients. Thirteen patients (2.6%) died in hospital and 70 (14%) died later during the follow-up period. Twenty-six reoperations were performed for recurrent angina (5.3%). Angina was initially relieved by operation in 97% of patients, but only 57% were alive and free of angina 6 years after their operation. Despite this, 91% of patients at last follow-up were in functional class I or II and 94% thought their symptoms were better than preoperatively. The mean postoperative time of onset of angina, estimated independently by family physicians and patients, was 33 months. The significant preoperative predictors of late death were a low left ventricular ejection fraction, previous myocardial infarction, prior cardiac surgery, increased cardiothoracic ratio and the number of coronary arteries with significant narrowing.

New Zealanders’ attitudes towards access to their electronic health records: Preliminary results from a national study using vignettes

This project investigates public attitudes towards sharing confidential personal health information held in electronic health records (EHRs). The project uses computer assisted telephone interviewing (CATI) to conduct a quantitative national survey of the attitudes of New Zealanders towards access to their personal health information using vignettes. Respondents are presented with vignettes which describe ways in which their health information might be used, and asked about their attitude to and consent for each type of access. The project outcome will be a specification of requirements for an e-consent model meeting the needs of most New Zealanders, thus enabling the potential benefits of electronically sharing confidential health information from EHRs. This article presents preliminary results from the first 1828 respondents. Respondents were most willing to share their information for the purpose of providing care. However, removing their name and address greatly increased the acceptability of sharing information for other purposes.

Urine glycosaminoglycans in a reference population effects of age body surface area and postmenopausal status

Urine glycosaminoglycans and hydroxyproline have been measured in an adult reference population containing significant numbers of those over 65 years. Urine concentrations of glycosaminoglycans remain constant into old age providing body weight is maintained and correlate significantly with body surface area. The urine ratio of glycosaminoglycans to creatinine rises markedly in women after menopause resulting in a bimodal frequency distribution. This ratio is worth further investigation as a marker of postmenopausal osteoporosis.

The Relationship between Vitamin D Status and Allergic Diseases in New Zealand Preschool Children

Recent research on vitamin D in young children has expanded from bone development to exploring immunomodulatory effects. Our aim was to investigate the relationship of vitamin D status and allergic diseases in preschool-aged children in New Zealand. Dried capillary blood spots were collected from 1329 children during late-winter to early-spring for 25(OH)D measurement by LC-MS/MS. Caregivers completed a questionnaire about their child’s recent medical history. Analysis was by multivariable logistic regression. Mean 25(OH)D concentration was 52(SD19) nmol/L, with 7% of children <25 nmol/L and 49% <50 nmol/L. Children with 25(OH)D concentrations ≥75 nmol/L (n = 29) had a two-fold increased risk for parent-report of doctor-diagnosed food allergy compared to children with 25(OH)D 50–74.9 nmol/L (OR = 2.21, 1.33–3.68, p = 0.002). No associations were present between 25(OH)D concentration and presence of parent-reported eczema, allergic rhinoconjunctivitis or atopic asthma. Vitamin D deficiency was not associated with several allergic diseases in these New Zealand preschool children. In contrast, high 25(OH)D concentrations were associated with a two-fold increased risk of parental-report food allergy. This increase supports further research into the association between vitamin D status and allergic disease in preschool children.

Water and nutrient intake in pregnant New Zealand women: association with wheeze in their infants at 18 months

The association between water and nutrient intake in pregnant women, and wheeze in their 18 month old infants, was investigated in a prospective study. Volunteers (n=369) recruited from northern New Zealand were visited in months 4 and 7 of pregnancy. At each visit anthropometric measurements were taken, diet assessed by 24-hour recall and 3-day food records and questionnaires determining personal details administered. Eighteen months after birth, infants were measured, and questions on infant feeding and wheeze asked. Overall, mothers reported 32% of their infants had wheezed in the last 12 months. After adjusting for significant covariates and energy intake, higher maternal intakes of dietary water (p=0.009) and manganese (p=0.024) were associated with decreased wheeze, and glucose (p=0.003) with increased wheeze. Prevalence of infant wheeze decreased 18.5% from the lower to the upper quartile of water intake, and 17.4% from the lower to the upper quartile of manganese intake. Wheeze was more common in Polynesian than European infants (41.8% vs 28.9%). Polynesian mothers consumed significantly less dietary water (median 451 g less) and manganese (median 1374 μg less) than European mothers per day. Glucose was only significant because of strong association with infant wheeze at extremely high maternal intakes of >40 g/day in ~10% of the subjects. There was no association between maternal dietary supplement intake and wheeze. Mothers estimated at high risk of infant wheeze consumed less tap water, whole grains, tea, fruit; and more fruit juice, soft drink, processed meat and fish products, and refined grain products. This is the first study to report an intergenerational association between maternal water, and glucose intake with infant wheeze.