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Biomedical subjects

C Guinot

Publications and source records attributed to C Guinot.

12 recordsLinked to original sources
PubMed2006

[Phototype, vitamin D status and bone mineral density among women at risk of osteoporosis].

PURPOSE: The aim of this study was to test the influence of phototype and vitamin D status feature on the bone mineral density (BMD) of the femoral neck in a group of middle-aged women considered at risk of osteoporosis (low levels of vitamin D [25(OH)D3<78 nmol/L] and hyperparathyroidism [parathormone level>36 pg/mL]). METHODS: This two-step study was conducted on 122 French women enrolled in the SUVIMAX (supplémentation en vitamines et minéraux antioxydants: antioxidant vitamin and mineral supplementation) cohort. The impact of various variables on BMD, including age, body mass index (BMI), vitamin D status, alcohol intake, sun exposure intensity and phototype was investigated using regression models. RESULTS: No statistical link was found between BMD and the variables documenting vitamin D status and parathormone levels, nor phototype. Nevertheless, fair phototypes tended to be associated with lower BMD values. However, BMD decreased with age and increased with BMI and physical activity level. CONCLUSIONS: Whatever their phototype, adult women concerned about precarious vitamin D status should undergo a vitamin D supplementation in combination with an adequate calcium intake all year long and a proper sun protection. Moreover, a physical activity maintenance should provide an additional benefit for prevention of osteoporosis.

Bone Density↗
PubMed2006

Reference ranges of skin micro-relief according to age in French Caucasian and Japanese women.

BACKGROUND/PURPOSE: The variation of skin surface morphological indicators according to age has not been frequently studied. The aim of this work was to establish French Caucasian and Japanese reference ranges of these indicators according to age. METHODS: Two studies were performed simultaneously in Paris and Sendai on 356 Caucasian and 120 Japanese healthy women aged from 20 to 80 years. Skin replicas were obtained from the volar forearm and analysed by interferometry. This analysis yielded 16 morphological indicators. Reference ranges according to age were established using the statistical methodology defined by Royston. RESULTS/DISCUSSION: Reference ranges were found for 15 out of the 16 parameters for the French women as well as for the Japanese women. The models' truthfulness will have to be confirmed using new samples, larger if possible. Moreover, non-parametric methods will be used in order to compare the results provided by these approaches.

Adult↗
PubMed2006

Self-reported skin sensitivity in a general adult population in France: data of the SU.VI.MAX cohort.

OBJECTIVE: This study aimed to examine the frequency of self-assessed facial skin sensitivity and its different patterns, and the relationship with gender and sun sensitivity in a general adult population. METHODS: A standardized 11-item questionnaire investigating reactions experienced during the past year was developed. The questions explored different patterns of skin sensitivity: pattern I (blushing related to vascular reactivity), pattern II (skin reactions to certain environmental conditions), pattern III (skin reactions after substance contact), and for women pattern IV ('breakout of spots' related to menstrual cycle). Additional items were addressed for women and men, including sun sensitivity. The questionnaire was administered to a large middle-aged population involved in the 'Supplément en Vitamines et Minéraux Antioxydants' (SU.VI.MAX) cohort. RESULTS: Sensitive facial skin was reported by 61% of the women (n = 5074) and 32% of the men (n = 3448), and the frequency decreased with age. The frequency of patterns I, II and III was greater for women (78, 72 and 58%, respectively) than for men (56, 48 and 28%) of comparable classes of age. The frequency of pattern IV was reported by 49% of premenopausal women, and skin reactions after shaving by 41% of the men. Sun sensitivity was found to be a major component of skin sensitivity. Factor analysis showed that individuals with fair phototype frequently evoked reactions associated with pattern I, and skin redness and burning sensations were related to certain environmental conditions (pattern II). CONCLUSION: Skin sensitivity is a common concern that declines with age and is relevant for men as well as for women.

Face↗
PubMed2002

[Effect of hormonal replacement therapy on cutaneous biophysical properties of menopausal women].

PURPOSE: The aim of this analysis was to study the possible effect of hormonal replacement therapy on some biophysical properties of the skin of menopausal women. SUBJECTS AND METHODS: A study was carried out on 106 menopausal, phototype I to IV women with clinically healthy skin. During the medical evaluation, the menopausal status, duration of the menopause, and, possible use of hormone replacement therapy and its duration were collected. A series of biophysical skin parameters in controlled environmental conditions was assessed on the face: sebum casual level, skin surface pH, skin colour, transepidermal water loss, capacitance, conductance, skin relief and temperature. The same parameters except for sebum were assessed on the forearm. Three sub-samples were defined according to the duration of the menopause and of hormone replacement therapy. RESULTS: The skin colour parameters revealed a greater red intensity value in menopausal women who had been treated for at least one year. In menopausal women who had been treated for at least 5 or 10 years, the biophysical measurements were significantly higher for the parameters evaluating hydration and sebum secretion, associated with higher values for the yellow intensity parameter and the skin relief parameters on the forehead. CONCLUSION: These results support the subjective impression and the clinical evaluation according to which hormonal replacement therapy could modify the development and the severity of some properties associated with skin ageing after the onset of menopause.

Aging↗
PubMed2001

Use of multiple correspondence analysis and cluster analysis to study dietary behaviour: food consumption questionnaire in the SU.VI.MAX. cohort.

Although the effects of individual foods or nutrients on the development of diseases and their risk factors have been investigated in many studies, little attention has been given to the effect of overall dietary patterns. The main objectives of this study were to identify dietary patterns and groups of subjects with similar food consumption habits, i.e. 'dietary profiles', using multiple correspondence analysis and cluster analysis. A food frequency questionnaire was sent to a large population-based sample (2923 women and 2,180 men), recruited among the 'SUpplementation en VItamines et Minéraux AntioXydants' (SU.VI.MAX.) cohort participants in France. The food items were dichotomised in order to focus the study on the highest levels of consumption. Multiple correspondence analysis allows the construction of principal components, which optimally summarise the data, and enables the construction of graphical displays. An interesting property of these graphical displays is that associations between food items can be observed on various projection planes, each category of each food item being located at the centre of gravity of the subjects corresponding to this category. An ascending hierarchical classification was unsuccessfully tried in order to determine clusters from these principal components. Therefore, a 'dissection' of the cloud of points was performed according to the orientation of the axes, providing a readily interpretable eight-dietary profiles typology for each sex. This statistical approach allows identification of particular dietary patterns and dietary profiles, which might be more appropriate in studies of diet-disease associations than the single food or nutrient approach that has dominated past epidemiological research.

Adult↗
PubMed2000

Epidemiologic determinants of skin photoaging: baseline data of the SU.VI.MAX. cohort.

BACKGROUND: Although skin disorders associated with long-term sun exposure account for high morbidity, only few data on sun-related preclinical skin changes are available in the general population. OBJECTIVE: In the present study we determined reference values for markers of photoaging in French adults, and we evaluated the relationship between photoaging, phototype, and both behavioral and environmental factors. METHODS: The SU.VI.MAX trial is a multicenter, national intervention trial on 12,735 adults living in France. A transverse analysis was performed on the inclusion data of the sample of volunteers between 45 and 60 years of age who underwent skin evaluation in 1995: 3057 women and 3606 men. Skin was evaluated by means of the Larnier skin photoaging photographic scale and a sun reactive skin type classification derived from those proposed by Fitzpatrick in 1976 and Césarini in 1977. RESULTS: The prevalence of skin photoaging, assessed as a dichotomous variable (from moderate/severe to very severe), was comparable in men and women in same age groups: in women, age group 45-49 years = 22%, 50-54 years = 36%, and 55-60 years = 42%; in men, age group 45-49 years = 17%, 50-54 years = 38%, and 55-60 years = 45%. After adjusting for body mass index, exposure to tobacco, and sunlight exposure, the only variables found to be related to skin photoaging in women were age (55-60 years age group: adjusted odds ratio [AOR] = 6.0, 95% confidence interval [CI] = 4.4-8.2), phototype IIIa, IIIb, and IV (AOR = 0.2, 95% CI = 0.1-0.4; AOR = 0.3, 95% CI = 0.2-0.6; and AOR = 0.4, 95% CI = 0.3-0.8; respectively), menopausal status (AOR = 1.4, 95% CI = 1.1-1.9), and geographic location (Southern France: AOR = 0. 7, 95% CI = 0.6-0.9), with a more pronounced effect in lighter phototypes I-II and a protective impact related to southern locations. No relationship was found between the use of oral contraceptives and skin photoaging. The age effect was also found in men (55-60 years age group: AOR = 10.4, 95% CI = 8.3-13.1) and geographic location (Southern France: AOR = 0.8, 95% CI = 0.6-0.9), with a most pronounced effect in darker phototypes (phototypes > IV: AOR = 2.8, 95% CI = 1.4-5.6). CONCLUSION: Our results suggest that the prevalence of skin photoaging in the adult French population is determined by age, sex, geographic location, and phototype. The continuation of this longitudinal study will allow for the investigation of the relationship between skin photoaging and the risk of the development of skin diseases.

Female↗
PubMed2000

Relationship between vitamin D status and skin phototype in general adult population.

A link between bone mineral density and skin color has been reported recently, and pigmentation has been shown to affect cutaneous vitamin D production. In the present study, we investigated the relationship between phototype, global self-assessed sun exposure, geographical location and vitamin D serum levels in 1191 French adults. When the factors were analyzed separately, individuals with lower phototypes as well as those with lower sun exposure showed significantly lower levels of vitamin D than those with darker phototypes or those with higher sun exposure. However, when factors were analyzed as a whole, the vitamin D status was no longer linked with the phototype, but with sun exposure and geographical location. Since phototypes and global self-assessments of sun exposure were positively linked, our data suggest that lower vitamin D levels in fair-skinned individuals are due to their sun exposure behavior.

Adult↗
PubMed2000

[Vitamin D concentrations in blood and skin phototype in a general adult population in France].

INTRODUCTION: A link between bone mineral density and skin color has been reported recently, and pigmentation has been shown to affect cutaneous vitamin D production. In the present study, we investigated the relationship between phototype, global self assessed sun exposure, geographical location and vitamin D serum levels in 1191 French adults. METHODS: Three multiple linear regression analyses were performed. The two first analyses to test separately the effect of phototype, and the effect of sun exposure on the vitamin D levels. Then, a third model was constructed, using both factors and geographical location. RESULTS: When the factors were analyzed separately, individuals with lower phototype showed significantly lower levels of vitamin D than those with darker phototype, as well as, individuals with lower sun exposure showed significantly lower levels of vitamin D than those with higher sun exposure. However in the global model, which takes into account phototype and sun exposure simultaneously together with the region of residence, the vitamin D status was no longer linked with the phototype, but with sun exposure and geographical location. CONCLUSION: Since phototype and global self-assessment of sun exposure were positively linked, our data suggest that lower vitamin D levels in fair-skinned individuals are due to their sun exposure behavior.

Adult↗
PubMedDate not supplied

Trachoma, flies and environmental factors in Burkina Faso.

The presence of flies is one of the earliest risk factors for trachoma and it has been suggested that flies could act as vectors for transmission of chlamydiae. A national trachoma survey was conducted in 1997 in Burkina Faso to (i) study the relationship between trachoma occurrence, flies, dirty faces and some environmental factors, and (ii) investigate the role of flies in the presence of trachoma. The country was stratified into eight groups of provinces and a random sample of 30 clusters was selected in each group. All children aged < 10 years were examined for the diagnosis of active trachoma (trachomatous inflammation which was follicular and/or intense) and the dirtiness of the face and the presence of flies on the face were recorded. The children's carers were questioned about the number of baths given and daily face-washing. Household heads were asked about ownership of cattle and small ruminants. The presence of latrines, a stable, and garbage collection inside the yard was noted. Among 16,514 children examined, 27.0% had active trachoma and 3.3% intense inflammatory trachoma. Flies were present on 11.2% of children's faces and 82.4% and 19.7% of these children had active and intense inflammatory trachoma, respectively. Among the 30.2% of children with dirty faces, 70.2% had active and 10.2% intense inflammatory trachoma. In multivariate analysis, at least one daily bath showed a protective effect on both active and intense inflammatory trachoma. Face-washing twice daily was found to be significantly protective for active trachoma in some regions. A strong association was demonstrated between the presence of flies and dirty faces (odds ratio = 334, 95% confidence interval 202-546). The presence of flies on children's faces, dirty faces and trachoma appeared to be strongly associated. Although the presence of flies may be a marker of socio-economic status and is probably linked with other trachoma risk factors, our data indicated that interventions targeting fly control should be an important issue in controlling trachoma.

Animals↗
PubMedDate not supplied

Daily variations in skin surface properties using mixed model methodology.

In order to explore the variations over the course of a day in certain skin biophysical properties, a study was conducted on 8 female volunteers. An assessment of several skin biophysical properties was carried out on the face and the volar forearm every 4 h over a period of 48 h. The biophysical parameters were assessed on the face for sebum secretion, skin surface pH, skin colour, transepidermal water loss, capacitance and skin surface temperature. The same parameters were measured on the volar forearm (excepted for sebum secretion). A statistical analysis based on mixed effect models was conducted. Four models, with different covariance structures, were successively tested. The analysis allowed us to identify a structure that repeated itself over time in the same way over each 24-hour period for capacitance on the forearm and for sebum secretion, skin surface pH and skin colour (L* and a* parameters) on the face. Mixed effect methodology is a powerful tool to analyse longitudinal data involving correlations among repeated measurements made on the same subject.

Adult↗